Currently on X87 platform we use only Double register (stack register) for Turbofan. So we directly use 1 as allocatable Double register number when setting up the default register configuration..
Currently on X87 platform we use only Double register (stack register) for Turbofan. So we directly
use 1 as allocatable Double register number when setting up the default register configuration..

It does not change the double register configuration of other platforms.

BUG=v8:4135
LOG=N

Review URL: https://codereview.chromium.org/1164813007

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#29005}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh