Previously, Object.values() and Object.entries() were piggy-backing on
Object.keys(). This meant that they would pre-filter non-enumerable properties,
violating the runtime behaviour of the methods. Unfortunately, this does not
match the current proposal text.

Also incorporates several tests verifying this behaviour based on tests included
in the ChakraCore implementation.

In this reland, the new patch fills up the longer-lasting FixedArray with
`undefined` to avoid the crash in Heap::Verify().

Originally reviewed at https://codereview.chromium.org/1637753004

BUG=v8:4663
LOG=N
R=adamk@chromium.org, rossberg@chromium.org, littledan@chromium.org

Review URL: https://codereview.chromium.org/1673673002

Cr-Commit-Position: refs/heads/master@{#33818}