SVG Text NG: Disable virtual/layout_ng_svg_text/ on older OSes

The feature must not be sensitive to OS versions. We can reduce
troubles on rebaseline-cl by disabling the test on older OSes.
We'll do rebaseline for them when we enable the feature by default.

This CL disable for macOS 11.0 too because its bot is unstable.

Bug: 1179585
Change-Id: I68acc6ea8da846d9e80922ea3a7df98d17a064fd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2854265


Auto-Submit: Kent Tamura <tkent@chromium.org>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/master@{#876963}