M35 Gardening: simd command line parameters is not being parsed

Crosswalk is printing the following error during startup:

Error: unrecognized flag --simd_object
Try --help for options

As side effect, other flags passed to V8 (like enable the GC interface, needed
by the extension tests) are being ignored.
Merge pull request #1769 from tmpsantos/next

M35 Gardening: simd command line parameters is not being parsed