Fix hcttest fail caused by cannot find clang. (#5012)

* Fix hcttest fail caused by cannot find clang.

All clang related commands are disabled.
Once clang is enabled, we can reenable these commands.

tools/clang/test/lit.cfg

@@ -190,9 +190,10 @@ def inferClang(PATH):
 
     return clang
 
-config.clang = inferClang(config.environment['PATH']).replace('\\', '/')
-if not lit_config.quiet:
-    lit_config.note('using clang: %r' % config.clang)
+if False: # HLSL Change - skip commands using clang.
+    config.clang = inferClang(config.environment['PATH']).replace('\\', '/')
+    if not lit_config.quiet:
+        lit_config.note('using clang: %r' % config.clang)
 
 # Plugins (loadable modules)
 # TODO: This should be supplied by Makefile or autoconf.
@@ -253,17 +254,19 @@ def makeMSABITriple(triple):
     # -win32 is not supported for non-x86 targets; use a default.
     return 'i686-pc-win32'
 
-config.substitutions.append( ('%clang_cc1',
-                              '%s -cc1 -internal-isystem %s -nostdsysteminc'
-                              % (config.clang,
-                                 getClangBuiltinIncludeDir(config.clang))) )
-config.substitutions.append( ('%clang_cpp', ' ' + config.clang +
-                              ' --driver-mode=cpp '))
-config.substitutions.append( ('%clang_cl', ' ' + config.clang +
-                              ' --driver-mode=cl '))
-config.substitutions.append( ('%clangxx', ' ' + config.clang +
-                              ' --driver-mode=g++ '))
-config.substitutions.append( ('%clang', ' ' + config.clang + ' ') )
+if False: # HLSL Change - skip commands using clang.
+    config.substitutions.append( ('%clang_cc1',
+                                  '%s -cc1 -internal-isystem %s -nostdsysteminc'
+                                  % (config.clang,
+                                     getClangBuiltinIncludeDir(config.clang))) )
+    config.substitutions.append( ('%clang_cpp', ' ' + config.clang +
+                                  ' --driver-mode=cpp '))
+    config.substitutions.append( ('%clang_cl', ' ' + config.clang +
+                                  ' --driver-mode=cl '))
+    config.substitutions.append( ('%clangxx', ' ' + config.clang +
+                                  ' --driver-mode=g++ '))
+    config.substitutions.append( ('%clang', ' ' + config.clang + ' ') )
+
 config.substitutions.append( ('%test_debuginfo', ' ' + config.llvm_src_root + '/utils/test_debuginfo.pl ') )
 config.substitutions.append( ('%itanium_abi_triple', makeItaniumABITriple(config.target_triple)) )
 config.substitutions.append( ('%ms_abi_triple', makeMSABITriple(config.target_triple)) )