v7.x: backport update to V8 5.5

This is a backport of the update to V8 5.5 for v7.x.

Additions are:

• Revert of the breaking UTF-8 decoder changes
• Patches to recover ABI/API compatibility with V8 5.4
• Patches to keep compatibility with all platforms supported by v7.x

/cc @nodejs/collaborators

CI: https://ci.nodejs.org/job/node-test-commit/7510 V8 tests: https://ci.nodejs.org/job/node-test-commit-v8-linux/543/

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

Affected core subsystem(s)

V8