[Target] Remove Target::GetScratchClangASTContext

Target doesn't really need to know about ClangASTContext more than any
other TypeSystem. We can create a method ClangASTContext::GetScratch for
anything who needs a ClangASTContext specifically instead of just a
generic TypeSystem.
diff --git a/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetItemInfoHandler.cpp b/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetItemInfoHandler.cpp
index b75a581..571e1d8 100644
--- a/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetItemInfoHandler.cpp
+++ b/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetItemInfoHandler.cpp
@@ -229,7 +229,7 @@
   lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
   ProcessSP process_sp(thread.CalculateProcess());
   TargetSP target_sp(thread.CalculateTarget());
-  ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
+  ClangASTContext *clang_ast_context = ClangASTContext::GetScratch(*target_sp);
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
 
   GetItemInfoReturnInfo return_value;
diff --git a/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetPendingItemsHandler.cpp b/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetPendingItemsHandler.cpp
index 05e34ab..be1b100 100644
--- a/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetPendingItemsHandler.cpp
+++ b/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetPendingItemsHandler.cpp
@@ -177,7 +177,7 @@
       // Next make the runner function for our implementation utility function.
       Status error;
       ClangASTContext *clang_ast_context =
-          thread.GetProcess()->GetTarget().GetScratchClangASTContext();
+          ClangASTContext::GetScratch(thread.GetProcess()->GetTarget());
       CompilerType get_pending_items_return_type =
           clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
       get_pending_items_caller =
@@ -228,7 +228,7 @@
   lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
   ProcessSP process_sp(thread.CalculateProcess());
   TargetSP target_sp(thread.CalculateTarget());
-  ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
+  ClangASTContext *clang_ast_context = ClangASTContext::GetScratch(*target_sp);
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
 
   GetPendingItemsReturnInfo return_value;
diff --git a/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetQueuesHandler.cpp b/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetQueuesHandler.cpp
index 7194c40..338d63d 100644
--- a/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetQueuesHandler.cpp
+++ b/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetQueuesHandler.cpp
@@ -191,7 +191,7 @@
 
     // Next make the runner function for our implementation utility function.
     ClangASTContext *clang_ast_context =
-        thread.GetProcess()->GetTarget().GetScratchClangASTContext();
+        ClangASTContext::GetScratch(thread.GetProcess()->GetTarget());
     CompilerType get_queues_return_type =
         clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
     Status error;
@@ -231,7 +231,7 @@
   lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
   ProcessSP process_sp(thread.CalculateProcess());
   TargetSP target_sp(thread.CalculateTarget());
-  ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
+  ClangASTContext *clang_ast_context = ClangASTContext::GetScratch(*target_sp);
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
 
   GetQueuesReturnInfo return_value;
diff --git a/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetThreadItemInfoHandler.cpp b/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetThreadItemInfoHandler.cpp
index 3dcfda2..22beda8 100644
--- a/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetThreadItemInfoHandler.cpp
+++ b/lldb/source/Plugins/SystemRuntime/MacOSX/AppleGetThreadItemInfoHandler.cpp
@@ -186,7 +186,7 @@
       // Also make the FunctionCaller for this UtilityFunction:
 
       ClangASTContext *clang_ast_context =
-          thread.GetProcess()->GetTarget().GetScratchClangASTContext();
+          ClangASTContext::GetScratch(thread.GetProcess()->GetTarget());
       CompilerType get_thread_item_info_return_type =
           clang_ast_context->GetBasicType(eBasicTypeVoid).GetPointerType();
 
@@ -237,7 +237,7 @@
   lldb::StackFrameSP thread_cur_frame = thread.GetStackFrameAtIndex(0);
   ProcessSP process_sp(thread.CalculateProcess());
   TargetSP target_sp(thread.CalculateTarget());
-  ClangASTContext *clang_ast_context = target_sp->GetScratchClangASTContext();
+  ClangASTContext *clang_ast_context = ClangASTContext::GetScratch(*target_sp);
   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_SYSTEM_RUNTIME));
 
   GetThreadItemInfoReturnInfo return_value;
diff --git a/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp b/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
index 69e59bc..08e3737 100644
--- a/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
+++ b/lldb/source/Plugins/SystemRuntime/MacOSX/SystemRuntimeMacOSX.cpp
@@ -412,7 +412,7 @@
 #endif
 
     ClangASTContext *ast_ctx =
-        m_process->GetTarget().GetScratchClangASTContext();
+        ClangASTContext::GetScratch(m_process->GetTarget());
     if (ast_ctx->getASTContext() &&
         m_dispatch_tsd_indexes_addr != LLDB_INVALID_ADDRESS) {
       CompilerType uint16 =