The new operator converts a float32 input to int32 through truncation.
I provide implementations of the new operator for x64, ia32, arm,
arm64, mips, mips64, and x87. @v8-ppc-ports, can you please take care
of the ppc implementation?

R=titzer@chromium.org, v8-arm-ports@googlegroups.com, v8-mips-ports@googlegroups.com, weiliang.lin@intel.com

Review URL: https://codereview.chromium.org/1583323004

Cr-Commit-Position: refs/heads/master@{#33346}