Force frame pointers for the backtrace test

Author: nagisa

src/test/run-pass/backtrace-debuginfo.rs

@@ -16,6 +16,7 @@
 // "enable" to 0 instead.
 
 // compile-flags:-g -Cllvm-args=-enable-tail-merge=0 -Cllvm-args=-opt-bisect-limit=0
+// compile-flags:-Cforce-frame-pointers=yes
 // ignore-pretty issue #37195
 // ignore-cloudabi spawning processes is not supported
 // ignore-emscripten spawning processes is not supported