Regression; loss of some names in --debug output

Since upgrading between the most recent releases (```closure-compiler-v20210106.jar``` to ```closure-compiler-v20210202.jar```) I notice a regression and a loss of useful information in the naming out of some ```--debug``` output.

Here's an example diff:

```
- $pause_rtt$jscomp$2$$ = this.$Tracer$_interval$;
+ $pause_rtt$jscomp$2$$ = this.$JSC$1730__interval$;

-$JSCompiler_prototypeAlias$$.$Plug_prototype$_toggle$ = function() {
+$JSCompiler_prototypeAlias$$.$JSC$1939__toggle$ = function() {

- }.bind($JSCompiler_StaticMethods_Door_prototype$open$self$$, $cap$jscomp$2$$), 500);
+ }.bind($JSCompiler_StaticMethods_JSC$1694_open$self$$, $cap$jscomp$2$$), 500);
```

I spent a few minutes trying to make a minimal test case, but time got the better of me as it was hard to stop the optimiser intervening to remove the code(!) Are these examples enough?

The compile flags are:

```
java -jar closure-compiler-v20210202.jar -O ADVANCED --formatting PRETTY_PRINT --debug
```