Revert "Make Dart heap size bigger when running pub."
Revert "Make Dart heap size bigger when running pub."

Reverts commit r29866.

BUG=

Review URL: https://codereview.chromium.org//58513005

git-svn-id: a962b240025cf0577aa172e20f49ccb159ba6be1@29869 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/pub,computmaxer/pub,cjkao/dart-pub,maxwellpeterson-wf/pub,dart-lang/pub