Revert "ARM: Use the shifter operand to merge in previous shift instructions."

This reverts r 22017

Reason: broke Nexus 7 GPU bots (see crbug.com/389198)

BUG=389198
LOG=n
TBR=machenbach@chromium.org, ulan@chromium.org

Review URL: https://codereview.chromium.org/359713004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22050 ce2b1a6d-e550-0410-aec6-3dcde31c8c00