Reland "Decouple SVG from SkFontMgr::RefDefault()"

This reverts commit 8bfbeca79d3a54763d72347a946c5cfe927b242d.

I was able to reproduce the ASAN issue by running the following
locally:
out/ASAN/dm --src tests gm --match mgr --verbose --nonativeFonts

The problem was that the original CL had inadvertanly introduced
a cycle between ToolUtils::TestFontMgr and TestSVGTypeface.

When parsing the SVG to create TestSVGTypeface, we don't need
a SkFontMgr because there should be no <text> tags to parse.

Original change's description:
> Revert "Decouple SVG from SkFontMgr::RefDefault()"
>
> This reverts commit 54be0f6f205b9a4ee39241a32df21589bdf2a986.
>
> Reason for revert: ASAN detects leaks
>
> Original change's description:
> > Decouple SVG from SkFontMgr::RefDefault()
> >
> > Instead of relying on the default SkFontMgr as a backup, this
> > explicitly sets the SkFontMgr to the test one (in our tests)
> > and uses and empty SkFontMgr if one was not set (e.g. by clients).
> >
> > Change-Id: I1ec4c710ec425be93ebe0d792ded172ea76838d2
> > Bug: b/305780908
> > Reviewed-on: https://skia-review.googlesource.com/c/skia/+/772660
> > Reviewed-by: Florin Malita <fmalita@google.com>
>
> Bug: b/305780908
> Change-Id: Ifbbaae570d9294bbb461db67320cbdada3d75341
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/774036
> Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Auto-Submit: Kevin Lubick <kjlubick@google.com>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>

Bug: b/305780908
Change-Id: Ie28c5be1011faa366bcbd870f69a57fbbc11ab43
Cq-Include-Trybots: luci.skia.skia.primary:Test-Debian10-Clang-GCE-CPU-AVX2-x86_64-Debug-All-BonusConfigs_ASAN
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/774116
Reviewed-by: Ben Wagner <bungeman@google.com>
13 files changed