Revert "[NFC] Explicitly pass a VFS when creating DiagnosticsEngine (#115852)"

Reverted for causing:
https://github.com/llvm/llvm-project/issues/117145

This reverts commit bdd10d9d249bd1c2a45e3de56a5accd97e953458.

1 files changed, 3 insertions, 6 deletions

diff --git a/clang/unittests/Frontend/CompilerInstanceTest.cpp b/clang/unittests/Frontend/CompilerInstanceTest.cpp
index 07329eb2..5cf548e9 100644
--- a/clang/unittests/Frontend/CompilerInstanceTest.cpp
+++ b/clang/unittests/Frontend/CompilerInstanceTest.cpp
@@ -13,7 +13,6 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/ToolOutputFile.h"
-#include "llvm/Support/VirtualFileSystem.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
@@ -54,8 +53,7 @@ TEST(CompilerInstance, DefaultVFSOverlayFromInvocation) {
   const char *Args[] = {"clang", VFSArg.c_str(), "-xc++", "-"};
 
   IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
-      CompilerInstance::createDiagnostics(*llvm::vfs::getRealFileSystem(),
-                                          new DiagnosticOptions());
+      CompilerInstance::createDiagnostics(new DiagnosticOptions());
 
   CreateInvocationOptions CIOpts;
   CIOpts.Diags = Diags;
@@ -89,9 +87,8 @@ TEST(CompilerInstance, AllowDiagnosticLogWithUnownedDiagnosticConsumer) {
   auto DiagPrinter = std::make_unique<TextDiagnosticPrinter>(
       DiagnosticsOS, new DiagnosticOptions());
   CompilerInstance Instance;
-  IntrusiveRefCntPtr<DiagnosticsEngine> Diags =
-      Instance.createDiagnostics(*llvm::vfs::getRealFileSystem(), DiagOpts,
-                                 DiagPrinter.get(), /*ShouldOwnClient=*/false);
+  IntrusiveRefCntPtr<DiagnosticsEngine> Diags = Instance.createDiagnostics(
+      DiagOpts, DiagPrinter.get(), /*ShouldOwnClient=*/false);
 
   Diags->Report(diag::err_expected) << "no crash";
   ASSERT_EQ(DiagnosticOutput, "error: expected no crash\n");