The InterpreterTester class cobbles together a JSFunction from
a manually created bytecode and feedback vector. However it's
fragile against design changes in the way literal arrays and
feedback vectors are handled. It's better to let it hand in
a feedback vector metadata object, and allow the system to
create the vector from that.

BUG=v8:5456

Review-Url: https://codereview.chromium.org/2652893010
Cr-Commit-Position: refs/heads/master@{#42684}