Move the build script from OSS-Fuzz's repo into ours, allowing us to
make changes without sending them a PR.
Change-Id: I557c3be2b6d9fd221ac7e6b1331bf3d53fd3ca51
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/217768
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
