Port 97def807

Original commit message:
    According to the ES2015 specification, bound functions are exotic
    objects, and thus don't need to be implemented as JSFunctions. So
    we introduce a new JSBoundFunction type to represent bound functions
    and make them optimizable. This already improves the performance of
    calling or constructing bound functions by 10-100x depending on the
    use case because we avoid the crazy dance between JavaScript and C++
    that was implemented in v8natives.js previously.

    There's still room for improvement in the performance of actually
    creating bound functions, which is also relevant in practice, but
    we already have a plan how to accomplish that later.

R=bmeurer@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=chromium:535408, chromium:571299, v8:4629
LOG=n

Review URL: https://codereview.chromium.org/1559473002

Cr-Commit-Position: refs/heads/master@{#33064}