[compiler-rt] [test] Disable MPROTECT on two builtin tests

[mgorny]

Summary

Introduce a new %run_nomprotect substitution to run tests that do not
work with MPROTECT enabled. This uses paxctl via a wrapper on NetBSD,
and evaluates to plain %run on other systems.

[mgorny]

Switch to using %run_nomprotect instead of extra %paxctl. This should be more consistent and should avoid potential issues with : on Windows.

compiler-rt/test/builtins/Unit/clear_cache_test.c

 // REQUIRES: native-run
 // UNSUPPORTED: arm, aarch64
-// RUN: %clang_builtins %s %librt -o %t && %run %t
+// RUN: %clang_builtins %s %librt -o %t && %paxctl_nomprotect %t && %run %t
 // REQUIRES: librt_has_clear_cache
 //===-- clear_cache_test.c - Test clear_cache -----------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

compiler-rt/test/builtins/Unit/enable_execute_stack_test.c

 // REQUIRES: native-run
-// RUN: %clang_builtins %s %librt -o %t && %run %t
+// RUN: %clang_builtins %s %librt -o %t && %paxctl_nomprotect %t && %run %t
 // REQUIRES: librt_has_enable_execute_stack
 //===-- enable_execute_stack_test.c - Test __enable_execute_stack ----------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

compiler-rt/test/lit.common.cfg.py

 config.clang = " " + " ".join(run_wrapper + [config.compile_wrapper, config.clang]) + " "
 config.target_cflags = " " + " ".join(target_cflags + extra_cflags) + " "
 
 if config.host_os == 'NetBSD':
   nb_commands_dir = os.path.join(config.compiler_rt_src_root,
                                  "test", "sanitizer_common", "netbsd_commands")
   config.netbsd_noaslr_prefix = ('sh ' +
                                  os.path.join(nb_commands_dir, 'run_noaslr.sh'))
+  config.substitutions.append( ('%paxctl_nomprotect', '/usr/sbin/paxctl +m') )
+else:
+  config.substitutions.append( ('%paxctl_nomprotect', ':') )