remove unneeded flags

Author: inbelic

clang/test/CodeGenHLSL/builtins/dot4add_i8packed.hlsl

@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -triple \
+// RUN: %clang_cc1 -finclude-default-header -triple \
 // RUN:   dxil-pc-shadermodel6.3-compute %s -emit-llvm -disable-llvm-passes -o - | \
 // RUN:   FileCheck %s -DTARGET=dx
-// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -triple \
+// RUN: %clang_cc1 -finclude-default-header -triple \
 // RUN:   spirv-pc-vulkan-compute %s -emit-llvm -disable-llvm-passes -o - | \
 // RUN:   FileCheck %s -DTARGET=spv