Revert "[clang] Use the VFS to get the OpenMP entry info (llvm#160935)"

This reverts commit 220ad03.

Author: ronlieb

clang/lib/CodeGen/CGOpenMPRuntime.cpp

@@ -1566,8 +1566,10 @@ static llvm::TargetRegionEntryInfo getEntryInfoFromPresumedLoc(
     SourceManager &SM = CGM.getContext().getSourceManager();
     PresumedLoc PLoc = SM.getPresumedLoc(BeginLoc);
 
-    if (CGM.getFileSystem()->exists(PLoc.getFilename()))
+    llvm::sys::fs::UniqueID ID;
+    if (llvm::sys::fs::getUniqueID(PLoc.getFilename(), ID)) {
       PLoc = SM.getPresumedLoc(BeginLoc, /*UseLineDirectives=*/false);
+    }
 
     return std::pair<std::string, uint64_t>(PLoc.getFilename(), PLoc.getLine());
   };

revert_patches.txt

@@ -22,3 +22,6 @@ needs more offload patches
 need to resole API changes downstream
 [Offload] Use Error for allocating/deallocating in plugins
 ---
+breaks smoke flags, wgs64
+[clang] Use the VFS to get the OpenMP entry info (#160935)
+---