Cherry-pick a Windows 7 timezone detection fix

Windows 7 has a 'bug' in one of its timezone APIs. ICU's
timezone detection code was hardened to work 'around' the
bug.

Upstream bug: https://unicode-org.atlassian.net/browse/ICU-20302
Upstream fix: https://github.com/unicode-org/icu/pull/315

TBR=gsathya@chromium.org,ftang@chromium.org

Bug: 913298
Test: See bug comment 35
Change-Id: Ib13b6a2809c629929490c5bfd73bee93b2c918c2
Reviewed-on: https://chromium-review.googlesource.com/c/1377557


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