Revert of ES6: Make function name configurable (patchset #10 id:220001 of https://codereview.chromium.org/960343002/)

Reason for revert:
Breaks Chrome browser test that checks Object.name

[16509:16509:0228/030150:INFO:CONSOLE(43)] "Uncaught Error: Clobbered Object.name getter", source: http://www.chromium.org:33611/assertions.js (43)

http://build.chromium.org/p/client.v8/builders/Linux%20Tests%20%28dbg%29%281%29/builds/2328/steps/browser_tests/logs/stdio

Original issue's description:
> ES6: Make function name configurable
>
> This is partially based on r21609 but that CL was incomplete.
>
> Function name is still non writable so one has to use defineProperty
> to change the actual value.
>
> BUG=v8:3333
> LOG=N
> R=adamk, mstarzinger@chromium.org
>
> Committed: https://crrev.com/f7790f7670c8d859455a98fcb90ff1b66af1eca7
> Cr-Commit-Position: refs/heads/master@{#26924}

TBR=adamk@chromium.org,mstarzinger@chromium.org,verwaest@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:3333

Review URL: https://codereview.chromium.org/969683002

Cr-Commit-Position: refs/heads/master@{#26933}