Hoist regenGlyphs out of per glyph loop

This positions to loop to be converted to
a bulk loop over the glyphs.

* rename fGlyphCache->fGrStrikeCache

Change-Id: Ie77d761905721cbdb52171117bac951cbca47af6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/254425
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Herb Derby <herb@google.com>
2 files changed