PPC: Correctify instanceof and make it optimizable.

PPC: Correctify instanceof and make it optimizable.

Port 5d875a57fa2e65c1a4a6b50aeb23c38299c3cfbc

Original commit message:
    The previous hack with HInstanceOfKnownGlobal was not only slower,
    but also very brittle and required a lot of weird hacks to support it. And
    what's even more important it wasn't even correct (because a map check
    on the lhs is never enough for instanceof).

    The new implementation provides a sane runtime implementation
    for InstanceOf plus a fast case in the InstanceOfStub, combined with
    a proper specialization in the case of a known global in CrankShaft,
    which does only the prototype chain walk (coupled with a code
    dependency on the known global).

    As a drive-by-fix: Also fix the incorrect Object.prototype.isPrototypeOf
    implementation.

R=bmeurer@chromium.org, jyan@ca.ibm.com, dstence@us.ibm.com, joransiu@ca.ibm.com
BUG=v8:4376
LOG=n

Review URL: https://codereview.chromium.org/1314263002

Cr-Commit-Position: refs/heads/master@{#30419}