Omit flaky encode-platform test for pic-8888 Mac CPU.

Bug: skia:6992
No-Try: true
Change-Id: I8141afb1706b1434bacc62f6b6f9b69876a92b2c
Reviewed-on: https://skia-review.googlesource.com/42680
Commit-Queue: Ben Wagner <benjaminwagner@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
diff --git a/infra/bots/recipes/test.py b/infra/bots/recipes/test.py
index 265fa50..916ab8d 100644
--- a/infra/bots/recipes/test.py
+++ b/infra/bots/recipes/test.py
@@ -382,6 +382,7 @@
       blacklist(['serialize-8888', 'gm', '_', test])
   if 'Mac' in bot and 'CPU' in bot and 'Release' in bot:
     # skia:6992
+    blacklist(['pic-8888', 'gm', '_', 'encode-platform'])
     blacklist(['serialize-8888', 'gm', '_', 'encode-platform'])
 
   # skia:4769