Fixes a segfault in Tooling when using pch's:
Clear the FileManager's stat cache in between running
translation units, as the stat cache loaded from a pch
is only valid for one compiler invocation.

llvm-svn: 161047
diff --git a/clang/lib/Tooling/Tooling.cpp b/clang/lib/Tooling/Tooling.cpp
index 5d41172..e93e0c9 100644
--- a/clang/lib/Tooling/Tooling.cpp
+++ b/clang/lib/Tooling/Tooling.cpp
@@ -212,6 +212,7 @@
   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);
 
   Compiler.resetAndLeakFileManager();
+  Files->clearStatCaches();
   return Success;
 }