These are upstream's prebuilt binaries of:
e9493171de  cmake-3.1.3-win32-x86.zip
ab6e7aee6a  strawberry-perl-5.20.2.1-32bit-portable.zip
4c4d195118  yasm-1.2.0-win32.exe

This is intentionally using yasm 1.2.0 rather than the latest 1.3.0 to match
Chromium's current bundled version. Chromium has additional patches, but they
all seem to be either in 1.2.0 or not relevant for us.

Also update extract.py a little to account for these.

BUG=430237

Change-Id: Iad6687e493900b25390d99882c7ceea62fff8b9b
Reviewed-on: https://boringssl-review.googlesource.com/3710
Reviewed-by: Adam Langley <agl@google.com>

Built from:
45f4d3fa8a2f61cc092ae461aac4cac1bab4ac6706f98274ea7f314dd315c6d0  cmake-3.1.3.tar.gz

Also drop in an extraction script.

Change-Id: I3487e9d432290a7dbabf854b927412c58c35d12b
Reviewed-on: https://boringssl-review.googlesource.com/3492
Reviewed-by: Adam Langley <agl@google.com>