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>

infra/bots/recipes/test.expected/Test-Mac-Clang-MacMini7.1-CPU-AVX-x86_64-Release.json

@@ -495,6 +495,10 @@
       "gm",
       "_",
       "makecolorspace",
+      "pic-8888",
+      "gm",
+      "_",
+      "encode-platform",
       "serialize-8888",
       "gm",
       "_",

infra/bots/recipes/test.py

@@ -382,6 +382,7 @@ def dm_flags(api, bot):
       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