tests: delete cat-and-grep-sanity-check

They were helper tests to check `cat` and `grep` behavior because
`Makefile` tests were relying on those utils. Now that we don't use
these tools, this test is no longer relevant.

Co-authored-by: Oneirical <[email protected]>

Author: jieyouxu

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -1,5 +1,4 @@
 run-make/branch-protection-check-IBT/Makefile
-run-make/cat-and-grep-sanity-check/Makefile
 run-make/extern-fn-reachable/Makefile
 run-make/incr-add-rust-src-component/Makefile
 run-make/jobserver-error/Makefile