We need to upload the full symbols for the download of debug symbols to
work.

This reverts commit 8e9ac1e08898685ed616cf9c72c908841e754d72.

This was mistakenly removed when merging changes from
firefox-developer-edition.

mozbuild already does equivalent stripping. The +20M install size (but
-10M package size) difference from 54 to 55 must come from somewhere
else.

Unused directly. Still pulled in transitively (through ffmpeg).