Generated code performs distinct floating multiply and add/subtract
operations. Tests fail when GCC uses mul-add to calculate the
expected result since these instructions provide higher accuracy due
to the lack of an intermediate round.

R=machenbach@chromium.org, mbrandy@us.ibm.com, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1812823008

Cr-Commit-Position: refs/heads/master@{#34953}