[HLSL] Simplify test (llvm#165743)

Simplify test that fcgl flag is expanded to the right flags.

Author: spall

clang/test/Driver/dxc_fcgl.hlsl

@@ -1,9 +1,5 @@
-// RUN: not %clang_dxc -fcgl -T lib_6_7 foo.hlsl -### %s 2>&1 | FileCheck %s
-// RUN: %clang_dxc -fcgl -T lib_6_7 %s -Xclang -verify
+// RUN: %clang_dxc -fcgl -T lib_6_7 %s -### %s 2>&1 | FileCheck %s
 
 // Make sure fcgl option flag which translated into "-emit-llvm" "-disable-llvm-passes".
 // CHECK: "-emit-llvm"
 // CHECK-SAME: "-disable-llvm-passes"
-
-// Make sure fcgl option not generate any diagnostics.
-// expected-no-diagnostics