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/Plugins/ObjectFile/JIT/ObjectFileJIT.cpp b/lldb/source/Plugins/ObjectFile/JIT/ObjectFileJIT.cpp
index 3103ed8..7b1627d 100644
--- a/lldb/source/Plugins/ObjectFile/JIT/ObjectFileJIT.cpp
+++ b/lldb/source/Plugins/ObjectFile/JIT/ObjectFileJIT.cpp
@@ -158,7 +158,7 @@
     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());
         if (m_symtab_ap.get() == NULL)
         {
             m_symtab_ap.reset(new Symtab(this));
@@ -200,7 +200,7 @@
     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());
         s->Printf("%p: ", static_cast<void*>(this));
         s->Indent();
         s->PutCString("ObjectFileJIT");