message: ThreadSanitizer plugin: match for loop variable with expected type
  Removes Clang warning ThreadSanitizerRuntime.cpp:591:21: warning:
  comparison of integers of different signs: 'int' and 'size_t' (aka
  'unsigned long') [-Wsign-compare]
diff: @@ -588,7 +588,7 @@ addr_t ThreadSanitizerRuntime::GetFirstNonInternalFramePc(
  ModuleSP runtime_module_sp = GetRuntimeModuleSP();
  StructuredData::Array *trace_array = trace->GetAsArray();
  - for (int i = 0; i < trace_array->GetSize(); i++) {
  + for (size_t i = 0; i < trace_array->GetSize(); i++) {
  if (skip_one_frame && i == 0)
  continue;
  