GN/Win: flesh out compiler flags.

This should turn on the basics: optimization, debug symbols, disabled RTTI.

Release builds compile monobench, and cl.exe isn't happy with 1.0/0.0 there, so I swapped that into infinity().

Also, gn format I skipped last time.

CQ_INCLUDE_TRYBOTS=master.client.skia.compile:Build-Win-MSVC-x86_64-Debug-GN-Trybot,Build-Win-MSVC-x86_64-Release-GN-Trybot

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3252

Change-Id: I8718d583e3fba4496b789eb25971462b972a5425
Reviewed-on: https://skia-review.googlesource.com/3252
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
2 files changed