[clang] [clang][driver][darwin] Switch back to using CanonicalName to identify the SDK instead of SupportedTargets (PR #178115)

[Cyndy Ishida via cfe-commits]

================
@@ -1914,14 +1914,16 @@ struct DarwinPlatform {
   DarwinSDKInfo inferSDKInfo() {
     assert(Kind == InferredFromSDK && "can infer SDK info only");
     llvm::Triple::OSType OS = getOSFromPlatform(Platform);
+    llvm::Triple::EnvironmentType EnvironmentType =
+        getEnvironmentTypeFromEnvironmentKind(Environment);
----------------
cyndyishida wrote:

I think it would be cleaner to hold onto the EnvironmentType in the `DarwinPlatform` type instead of needing a helper function to convert.

https://github.com/llvm/llvm-project/pull/178115