Limit run-make tests using -Zbuild-std to nightly

See #130634

Author: cuviper

tests/run-make/compiler-builtins/rmake.rs

@@ -11,6 +11,7 @@
 // wasm and nvptx targets don't produce rlib files that object can parse.
 //@ ignore-wasm
 //@ ignore-nvptx64
+//@ only-nightly
 
 #![deny(warnings)]
 

tests/run-make/thumb-none-cortex-m/rmake.rs

@@ -13,6 +13,7 @@
 //! - thumbv7m-none-eabi (Bare Cortex-M3)
 
 //@ only-thumb
+//@ only-nightly
 
 use std::path::PathBuf;