Revert of Set the current context to the function's context when entering to LAP. (patchset #14 id:540001 of https://codereview.chromium.org/2770003002/ )

Reason for revert:
Speculative: Seems to break webkit_unit_tests:
https://build.chromium.org/p/tryserver.v8/builders/v8_linux_blink_rel/builds/23247
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Mac/builds/11038

Original issue's description:
> Set the current context to the function's context when entering to LAP.
>
> In case of LAP(lazy accessor pair), the function's creation context
> must be equal to the accessor holder's creation context, so this CL
> changes the current context to the accessor holder's creation context.
>
> BUG=v8:6156
>
> Review-Url: https://codereview.chromium.org/2770003002
> Cr-Commit-Position: refs/heads/master@{#46406}
> Committed: https://chromium.googlesource.com/v8/v8/+/18e73287dc65452bc2f952fc005b2251fc32c15a

TBR=jochen@chromium.org,verwaest@chromium.org,mstarzinger@chromium.org,tebbi@google.com,yukishiino@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6156

Review-Url: https://codereview.chromium.org/2973593002
Cr-Commit-Position: refs/heads/master@{#46408}