Do not specify target triple for codegen test so it also runs on msvc builds

Author: jhorstmann

tests/codegen/issues/issue-123712-str-to-lower-autovectorization.rs

@@ -1,7 +1,5 @@
 //@ only-x86_64
-//
-//@ needs-llvm-components: x86
-//@ compile-flags: --target=x86_64-unknown-linux-gnu -Copt-level=3
+//@ compile-flags: -C opt-level=3
 #![crate_type = "lib"]
 #![no_std]
 #![feature(str_internals)]