deps: cherry-pick fa4ec9f from V8 upstream

[jbajwa]

Original commit message:

[date] Refactor PosixTimezoneCache for different OS

Follow up on https://codereview.chromium.org/2740353002. Created
PosixDefaultTimezoneCache which is a subclass of PosixTimezoneCache
containing definition of LocalTimezone and LocalTimeOffset which is
separate for different OS.

R=littledan@chromium.org, ulan@chromium.org

BUG=v8:6578
LOG=N

Change-Id: I58342893aeefe79ac50e1df041d614fc473f15bf
Reviewed-on: https://chromium-review.googlesource.com/568686
Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Commit-Queue: Jaideep Bajwa <bjaideep@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#46604}

Fixes: #14080

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Affected core subsystem(s)

deps/v8

[jbajwa]

/cc @bnoordhuis @gireeshpunathil

[jbajwa]

@gireeshpunathil
I don't have the permission to kick off the CI jobs. Could you help kicking off these jobs?
CI: https://ci.nodejs.org/job/node-test-commit
V8 CI: https://ci.nodejs.org/job/node-test-commit-v8-linux

[bnoordhuis]

Thanks, LGTM.

Node CI: https://ci.nodejs.org/job/node-test-pull-request/9463/
V8 CI: https://ci.nodejs.org/job/node-test-commit-v8-linux/837/

[jbajwa]

@bnoordhuis
Hi Ben, if this PR is good to land could you help with landing it? Also, do we need another set of runs? since I rebased it.
Thanks.

[bnoordhuis]

Sorry @jbajwa, I thought you had commit access. This PR puts us in the somewhat awkward position that bumping the V8 patch level means our 6.0.53 isn't upstream's 6.0.53.

I fixed it (what's in a name) by bumping both the patch level and the build number. Landed in 8096791, cheers.

[MylesBorins]

This does not land cleanly in LTS. Please feel free to manually backport by following the guide. Please also feel free to replace do-not-land if it is being backported