Allow calling HandleAllocator::reserve with MAX_UINT. BUG=angleproject:1052 Change-Id: I03883799ef334f39c9e855a0a4b7af1ab02d5da9 Reviewed-on: https://chromium-review.googlesource.com/282414 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Minmin Gong <mgong@microsoft.com>