[msan] Handle llvm.[us]cmp (starship operator) (#125804)

Apply handleShadowOr to llvm.[us]cmp. Previously, llvm.[su]cmp was correctly handled heuristically when each parameter type is the same as the return type (e.g., `call i8 @llvm.ucmp.i8.i8(i8 %x, i8 %y)`) but handled incorrectly by visitInstruction when the return type is different e.g., (`call i8 @llvm.ucmp.i8.i62(i62 %x, i62 %y)`, `call <4 x i8> @llvm.ucmp.v4i8.v4i32(<4 x i32> %x, <4 x i32> %y)`).

Updates the tests from #125790

Author: thurstond

llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

@@ -4945,6 +4945,12 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
       break;
     }
 
+    case Intrinsic::scmp:
+    case Intrinsic::ucmp: {
+      handleShadowOr(I);
+      break;
+    }
+
     default:
       if (!handleUnknownIntrinsic(I))
         visitInstruction(I);