Override UI test default strip debuginfo behavior

Author: jieyouxu

tests/ui/debuginfo/backtrace-line-tables-only.rs

@@ -4,7 +4,7 @@
 // ignore-tidy-linelength
 //@ ignore-windows
 //@ run-pass
-//@ compile-flags: -Cdebuginfo=line-tables-only
+//@ compile-flags: -Cdebuginfo=line-tables-only -Cstrip=none
 #![feature(backtrace_frames)]
 
 use std::backtrace::{self, Backtrace};