Make a more complete fix for always supplying an execution context when getting byte sizes from types.

There was a test in the test suite that was triggering the backtrace logging output that requested that the client pass an execution context. Sometimes we need the process for Objective C types because our static notion of the type might not align with the reality when being run in a live runtime.

Switched from an "ExecutionContext *" to an "ExecutionContextScope *" for greater ease of use.

llvm-svn: 228892
diff --git a/lldb/source/Core/ValueObjectVariable.cpp b/lldb/source/Core/ValueObjectVariable.cpp
index ed2aeb3..c86bece 100644
--- a/lldb/source/Core/ValueObjectVariable.cpp
+++ b/lldb/source/Core/ValueObjectVariable.cpp
@@ -112,7 +112,7 @@
     if (!type.IsValid())
         return 0;
     
-    return type.GetByteSize(&exe_ctx);
+    return type.GetByteSize(exe_ctx.GetBestExecutionContextScope());
 }
 
 lldb::ValueType