skpbench: Support .svg files

Bug: skia:
Change-Id: I0337757f635c631870c02a65f8784fc190d1435e
Reviewed-on: https://skia-review.googlesource.com/137540
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
2 files changed