Blacklist hanging test.

Blacklist gr_mipmap_build_511x512 for nanobench on the Acer Chromebook
R13 Convertible to avoid timeouts for Release build.

Bug: skia:8187
No-Try: true
Change-Id: Ic63fb705a6a6cc6576978c96a8dd5206dc59ba0d
Reviewed-on: https://skia-review.googlesource.com/143162
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Ben Wagner <benjaminwagner@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed