Add SSE2 and SSE4.1 limited builds.

As the machines we test on get fancier and fancier, we're losing
coverage of older instruction sets.  This adds a flag to skip
CPU detection, and two new builds to test SSE2 and SSE4.1.

Change-Id: Ie28518b30860f90c80f71020e64e3696a7047021
Commit-Queue: Mike Klein <>
Commit-Queue: Brian Osman <>
Auto-Submit: Mike Klein <>
Reviewed-by: Brian Osman <>
4 files changed