Fix an integer overflow in Islamic calendar

When the time is set to MAX_MILLIS, Islamic calendar
year and month calculation results in an integer overflow.

TBR=littledan@chromium.org
Bug: 801602
Test: See the bug (v8 test will be added)
Change-Id: Ifcb6907de81de83b690f76a536818054815a15a7
Reviewed-on: https://chromium-review.googlesource.com/865524


Reviewed-by: Jungshik Shin <jshin@chromium.org>