Do not compile 'all' on memory trybots, some targets fail otherwise

BUG=408285
R=glider@chromium.org

Review URL: https://codereview.chromium.org/510913004

Cr-Commit-Position: refs/heads/master@{#292375}

testing/buildbot/chromium_memory_trybot.json

 {
-  "compile_targets": [
-    "all"
-  ],
   "gtest_tests": [
     {
       "test": "accessibility_unittests",