[llvm] Fix build after llvm#161260

The modular build was failing due to a missing include.

Author: jansvoboda11

llvm/include/llvm/Transforms/Instrumentation/GCOVProfiler.h

@@ -14,6 +14,7 @@
 
 #include "llvm/IR/PassManager.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Transforms/Utils/Instrumentation.h"
 
 namespace llvm {