Disable SkSG unit test for G3

Speculative fix for G3 rolls.

TBR=
Change-Id: I937d3b432cdf0c0d654f0976fd683acba39470ef
Reviewed-on: https://skia-review.googlesource.com/90405
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed