remove use of Mutex in favour of std::{,recursive_}mutex

This is a pretty straightforward first pass over removing a number of uses of
Mutex in favor of std::mutex or std::recursive_mutex. The problem is that there
are interfaces which take Mutex::Locker & to lock internal locks. This patch
cleans up most of the easy cases. The only non-trivial change is in
CommandObjectTarget.cpp where a Mutex::Locker was split into two.

llvm-svn: 269877
diff --git a/lldb/source/Symbol/ObjectFile.cpp b/lldb/source/Symbol/ObjectFile.cpp
index 36196b0..62cde26 100644
--- a/lldb/source/Symbol/ObjectFile.cpp
+++ b/lldb/source/Symbol/ObjectFile.cpp
@@ -600,7 +600,7 @@
     ModuleSP module_sp(GetModule());
     if (module_sp)
     {
-        lldb_private::Mutex::Locker locker(module_sp->GetMutex());
+        std::lock_guard<std::recursive_mutex> guard(module_sp->GetMutex());
         Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
         if (log)
             log->Printf ("%p ObjectFile::ClearSymtab () symtab = %p",
@@ -620,7 +620,7 @@
             ModuleSP module_sp(GetModule());
             if (module_sp)
             {
-                lldb_private::Mutex::Locker locker(module_sp->GetMutex());
+                std::lock_guard<std::recursive_mutex> guard(module_sp->GetMutex());
                 CreateSections(*module_sp->GetUnifiedSectionList());
             }
         }