Write test for Rust fragile hardening
We should write some tests to ensure that asan is working to check memory leaks, dangling pointers, and so on. I know that #25386 (moved) links asan, but I don't know if it actually checks stuff that we want checked. We should check that it checks what we want checked.
I envision this looking like a
test_fragile_hardening.c (or a series of such files) and some helper Rust code that does some bad behavior and a wrapper that ensures that it crashes.
Landing this requires #25386 (moved), but writing it does not; just assume that Rust and C can arbitrarily call each other (with the proper boilerplate), and asan is supposed to catch everything that it catches in C.