Add --no-cuda-version-check in unknown-std.cpp

[kkwli0]

Summary

This unit test fails on the system that has CUDA Toolkit 9.0 installed. And CUDA 9 does not support GPU arch sm_20. It results in the following error.

clang-6.0: error: GPU arch sm_20 is supported by CUDA versions between 7.0 and 8.0 (inclusive), but installation at /usr/local/cuda is 9.0.  Use --cuda-path to specify a different CUDA install, pass a different GPU arch with --cuda-gpu-arch, or pass --no-cuda-version-check.

[tra]

Ideally the tests should be hermetic and should use mock CUDA installation that comes with the tests. E.g. --cuda-path=%S/Inputs/CUDA/usr/local/cuda

[kkwli0]

Using a mock CUDA installation works too.

test/Driver/unknown-std.cpp

 // This file checks output given when processing C++/ObjC++ files.
 // When user selects invalid language standard
 // print out supported values with short description.
 
 // RUN: not %clang %s -std=foobar -c 2>&1 | FileCheck --match-full-lines %s
 // RUN: not %clang -x objective-c++ %s -std=foobar -c 2>&1 | FileCheck --match-full-lines %s
-// RUN: not %clang -x cuda -nocudainc -nocudalib %s -std=foobar -c 2>&1 | FileCheck --match-full-lines --check-prefix=CHECK --check-prefix=CUDA %s
+// RUN: not %clang -x cuda -nocudainc -nocudalib --cuda-path=%S/Inputs/CUDA/usr/local/cuda %s -std=foobar -c 2>&1 | FileCheck --match-full-lines --check-prefix=CHECK --check-prefix=CUDA %s
 
 // CHECK: error: invalid value 'foobar' in '-std=foobar'
 // CHECK-NEXT: note: use 'c++98' or 'c++03' for 'ISO C++ 1998 with amendments' standard
 // CHECK-NEXT: note: use 'gnu++98' or 'gnu++03' for 'ISO C++ 1998 with amendments and GNU extensions' standard
 // CHECK-NEXT: note: use 'c++11' for 'ISO C++ 2011 with amendments' standard
 // CHECK-NEXT: note: use 'gnu++11' for 'ISO C++ 2011 with amendments and GNU extensions' standard
 // CHECK-NEXT: note: use 'c++14' for 'ISO C++ 2014 with amendments' standard
 // CHECK-NEXT: note: use 'gnu++14' for 'ISO C++ 2014 with amendments and GNU extensions' standard