This patch implements a recent spec change [1] which increases the
bounds of precision for toFixed, toExponential and toPrecision.
The bounds are a compromise between SpiderMonkey and the other
engines.

[1] https://github.com/tc39/ecma262/pull/857

Bug: v8:6539
Cq-Include-Trybots: master.tryserver.v8:v8_linux_noi18n_rel_ng
Change-Id: I877aa35e08f3dcda63f5f9181fdecf3c227f2c35
Reviewed-on: https://chromium-review.googlesource.com/553378
Commit-Queue: Daniel Ehrenberg <littledan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46793}