ignore tests broken while cross compiling

Author: pietroalbini

tests/run-make/doctests-keep-binaries/rmake.rs

@@ -1,3 +1,5 @@
+//@ ignore-cross-compile attempts to run the doctests
+
 // Check that valid binaries are persisted by running them, regardless of whether the
 // --run or --no-run option is used.
 

tests/run-make/target-cpu-native/rmake.rs

@@ -3,6 +3,8 @@
 // warnings when used, and that binaries produced by it can also be successfully executed.
 // See https://github.com/rust-lang/rust/pull/23238
 
+//@ ignore-cross-compile target-cpu=native doesn't work well when cross compiling
+
 use run_make_support::{run, rustc};
 
 fn main() {