tests/debuginfo/macro-stepping.rs: Add revisions default-mir-passes, no-SingleUseConsts-mir-pass

To prevent the test from regressing both with and without
`SingleUseConsts` MIR pass.

Author: Enselic

tests/debuginfo/macro-stepping.rs

@@ -14,8 +14,10 @@
 #[macro_use]
 extern crate macro_stepping; // exports new_scope!()
 
-//@ compile-flags:-g -Zmir-enable-passes=-SingleUseConsts
-// SingleUseConsts shouldn't need to be disabled, see #128945
+//@ compile-flags:-g
+// FIXME(#128945): It should not be necessary to disable SingleUseConsts. Revisions should not be needed in this test.
+//@ revisions:default-mir-passes no-SingleUseConsts-mir-pass
+//@ [no-SingleUseConsts-mir-pass] compile-flags:-Zmir-enable-passes=-SingleUseConsts
 
 // === GDB TESTS ===================================================================================
 
@@ -48,7 +50,7 @@ extern crate macro_stepping; // exports new_scope!()
 //@ gdb-check:[...]#inc-loc2[...]
 //@ gdb-command:next
 //@ gdb-command:frame
-//@ gdb-check:[...]#inc-loc3[...]
+//@ [no-SingleUseConsts-mir-pass] gdb-check:[...]#inc-loc3[...]
 
 // === LLDB TESTS ==================================================================================