Port run-make/sysroot-crates-are-unstable to rmake

Author: Zalathar

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -21,6 +21,5 @@ run-make/reproducible-build/Makefile
 run-make/rlib-format-packed-bundled-libs/Makefile
 run-make/split-debuginfo/Makefile
 run-make/symbol-mangling-hashed/Makefile
-run-make/sysroot-crates-are-unstable/Makefile
 run-make/translation/Makefile
 run-make/x86_64-fortanix-unknown-sgx-lvi/Makefile

tests/run-make/sysroot-crates-are-unstable/Makefile

@@ -0,0 +1,5 @@
+use run_make_support::python_command;
+
+fn main() {
+    python_command().arg("test.py").run();
+}