Disable tests/run-make/mte-ffi

See RUST-141600: this test is broken in two ways:

1. This test triggers `-Wincompatible-pointer-types` on GCC 14.
2. This test requires ARMv8.5+ w/ MTE extensions enabled, but GHA CI
   runner hardware do not have this enabled.

Author: jieyouxu

tests/run-make/mte-ffi/rmake.rs

@@ -2,6 +2,13 @@
 //! FFI boundaries (C <-> Rust). This test does not require MTE: whilst the test will use MTE if
 //! available, if it is not, arbitrary tag bits are set using TBI.
 
+//@ ignore-test (FIXME #141600)
+//
+// FIXME(#141600): this test is broken in two ways:
+// 1. This test triggers `-Wincompatible-pointer-types` on GCC 14.
+// 2. This test requires ARMv8.5+ w/ MTE extensions enabled, but GHA CI runner hardware do not have
+//    this enabled.
+
 //@ only-aarch64-unknown-linux-gnu
 // Reason: this test is only valid for AArch64 with `gcc`. The linker must be explicitly specified
 // when cross-compiling, so it is limited to `aarch64-unknown-linux-gnu`.