Extend stat query APIs to explicitly specify if the query is for
a file or directory, allowing just a stat call if a file descriptor
is not needed.

Doing just 'stat' is faster than 'open/fstat/close'.
This has the effect of cutting down system time for validating the input files of a PCH.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169831 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Basic/FileManagerTest.cpp b/unittests/Basic/FileManagerTest.cpp
index 0a83a3a..a55fcbf 100644
--- a/unittests/Basic/FileManagerTest.cpp
+++ b/unittests/Basic/FileManagerTest.cpp
@@ -51,7 +51,7 @@
 
   // Implement FileSystemStatCache::getStat().
   virtual LookupResult getStat(const char *Path, struct stat &StatBuf,
-                               int *FileDescriptor) {
+                               bool isFile, int *FileDescriptor) {
     if (StatCalls.count(Path) != 0) {
       StatBuf = StatCalls[Path];
       return CacheExists;