SINGLE_FILE_BINARY_ENCODE=1 crashes at run-time with "Uncaught SyntaxError: octal escape sequences can't be used in untagged template literals or in strict mode code"

Please include the following in your bug report:

**Version of emscripten/emsdk:**
4.0.20

**Failing command line in full:**
Compilation works, error is at run-time

**Full link command and output with `-v` appended:**
Even for runtime issues it helps a lot if you can include the full link command.
Adding `-v` to the link command will show all of the sub-commands run which
can help us diagnose your issue.

```
-sSINGLE_FILE=1
-sSINGLE_FILE_BINARY_ENCODE=1
-sMODULARIZE=1
-sENVIRONMENT=web
```

Hi emscripten team!

I'm using the new binary encoding for SINGLE_FILE mode in my library. Some users are now reporting that they are seeing an error: `Uncaught SyntaxError: octal escape sequences can't be used in untagged template literals or in strict mode code`. Are there some caveats of this feature that we should be aware of, especially in bundling scenarios?

The MDN page for the syntax error is here:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Deprecated_octal_escape_sequence

I'm working with the user to get more information about their bundling setup and a reproducer, but that may take a while.