android envsetup: Move some webview-specific configuration into gyp_webview.

Engineers working on webview always call gyp_webview instead of gyp_chromium,
so there's no need to keep these settings in env vars.

BUG=330631
R=torne@chromium.org

Review URL: https://codereview.chromium.org/151603005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248723 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248723
Disable failing blink_heap_unittests on Android

BUG=340591
R=ager@chromium.org
TBR=ager@chromium.org

Review URL: https://codereview.chromium.org/140893007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248724 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248724