[Interpreter] Add support for loading literals from the constant pool.

[Interpreter] Add support for loading literals from the constant pool.

Adds support to the interpreter for loading literals from the constant pool.
Adds the LoadConstant bytecode and makes use of it for loading large Smis and
HeapObject literals.

Also removes unused HandleVector from utils.h.

BUG=v8:4280
LOG=N

Review URL: https://codereview.chromium.org/1321663003

Cr-Commit-Position: refs/heads/master@{#30450}