[clang] [llvm] [ASan] Skip explicit check of 'xnack' feature for gfx1250 && gfx1251. (PR #166754)

[Amit Kumar Pandey via llvm-commits]

================
@@ -161,6 +161,9 @@ enum ArchFeatureKind : uint32_t {
 
   // WGP mode is supported.
   FEATURE_WGP = 1 << 9,
+
+  // Xnack is available by default
+  FEATURE_XNACK_ALWAYS = 1 << 10
----------------
ampandey-1995 wrote:

`FEATURE_XNACK` is actually a part of targetID that has to be coordinated with rocm runtime. FEATURE_XNACK is checked when `--offload-arch=gfxXXX:xnack+` is mentioned or `--offload-arch=gfxXXX:xnack-`.

There is no requirement of `xnack+` or `xnack-` for these gfx1250 or gfx1251 so the driver doesn't need to check `xnack` by extracting features from TargetID  source code. 

This was actually an [objection](https://github.com/AMD-Lightning-Internal/llvm-project/pull/781#discussion_r2046790472) raised by @yxsamliu in internal PR [781](https://github.com/AMD-Lightning-Internal/llvm-project/pull/781) for which I tried solving in another internal PR [1705](https://github.com/AMD-Lightning-Internal/llvm-project/pull/1705) but was not successful.

Now that objection I think is resolved here in upstream PR, @yxsamliu is this fix Ok?

https://github.com/llvm/llvm-project/pull/166754