[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 https://github.com/llvm/llvm-project/pull/125790
