Partial revert 131205: Use build_for_tool= on the memory bots.
Partial revert 131205: Use build_for_tool= on the memory bots.

Only master.chromium.memory.fyi got reverted. master.chromium.fyi did not.

This is breaking all the cros bots because the target_arch flag is missing.

TBR=rnk
BUG=109780

Review URL: http://codereview.chromium.org/10158008

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@133153 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build