[Error Handling] Fix DxcContainerBuilder error handling

[bob80905]

Some error handling changes were incorrectly made to the container assembler, as described in the issue below.
This is bad because the API protocol for error handling must remain consistent across all functions. This PR
aims to restore the correct semantic meaning of returning bad HR values.
Fixes #7051

[tex3d]

If this succeeded testing without the suggested change to check valHR before hashing, we are missing a test that makes sure it doesn't hash the shader even when validation fails.

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff 070d0d5a2beacef9eeb51037a9b04665716fd6f3 9194c5300d03c3163779108d8d27c86dce6afd4b -- lib/DxilContainer/DxcContainerBuilder.cpp tools/clang/tools/dxclib/dxc.cpp tools/clang/unittests/HLSL/ValidationTest.cpp

View the diff from clang-format here.

diff --git a/tools/clang/unittests/HLSL/ValidationTest.cpp b/tools/clang/unittests/HLSL/ValidationTest.cpp
index cb2a5ce28..e7d3bfaeb 100644
--- a/tools/clang/unittests/HLSL/ValidationTest.cpp
+++ b/tools/clang/unittests/HLSL/ValidationTest.cpp
@@ -1228,7 +1228,7 @@ TEST_F(ValidationTest, ValidationFailNoHash) {
   VERIFY_IS_NOT_NULL(pHeader);
 
   BYTE ZeroHash[DxilContainerHashSize] = {0, 0, 0, 0, 0, 0, 0, 0,
-                                        0, 0, 0, 0, 0, 0, 0, 0};
+                                          0, 0, 0, 0, 0, 0, 0, 0};
 
   // Should be equal, this proves the hash isn't written when validation fails
   VERIFY_ARE_EQUAL(memcmp(ZeroHash, pHeader->Hash.Digest, sizeof(ZeroHash)), 0);

• Check this box to apply formatting changes to this branch.

[tex3d]

Nit: the comment could say why the shader is expected to fail validation, otherwise it might not be obvious. That was the initial issue that tripped me up when reading the test code.

I still would have preferred we assembled IR instead of compiled HLSL, since that's what we should be using in validation tests.

Suggested change

	// we need any shader that will pass compilation but fail validation
	// We need any shader that will pass compilation but fail validation.
	// This shader reads from uninitialized 'float a', which works for now.

[tex3d]

Nit: I think Result should be renamed to be clear that it's zeros, like ZeroHash. That way if you had a failure in the VERIFY macro, you would see that it's comparing with ZeroHash and understand what was expected without having to read this source code.

[tex3d]

Nit: Comment out of date.

Suggested change

	// Should be unequal, this proves the hash isn't written when validation fails
	// Should be equal, this proves the hash isn't written when validation fails