[linux-port] Disable (on Uinux) unit tests that rely on d3d12shader.h

Since we don't have d3d12shader.h on Linux/macOS, I am disabling the
unit tests that depend on it.

I am currently disabling entire files that depend on this header.
It is possible to have a more fine-grained change to only disable
specific tests within these files, although that would be a more intrusive
change and not necessary at the moment.

tools/clang/unittests/HLSL/CMakeLists.txt

@@ -65,17 +65,19 @@ set(HLSL_IGNORE_SOURCES
   MSFileSysTest.cpp
   RewriterTest.cpp
   ShaderOpTest.cpp
+  D3DReflectionDumper.cpp
+  DxilContainerTest.cpp
+  FileCheckerTest.cpp
+  ValidationTest.cpp
+  CompilerTest.cpp
   )
 
 add_clang_unittest(clang-hlsl-tests
   AllocatorTest.cpp
-  CompilerTest.cpp
   DxcTestUtils.cpp
-  DxilContainerTest.cpp
   DxilModuleTest.cpp
   DXIsenseTest.cpp
   ExtensionTest.cpp
-  FileCheckerTest.cpp
   FileCheckForTest.cpp
   FunctionTest.cpp
   HLSLTestOptions.cpp
@@ -84,7 +86,6 @@ add_clang_unittest(clang-hlsl-tests
   OptionsTest.cpp
   SystemValueTest.cpp
   TestMain.cpp
-  ValidationTest.cpp
   VerifierTest.cpp
   )