Modifies the BytecodeArrayBuilder to create register operands which are
negative. This reduces the number of instructions to access registers
by the interpreter and allows us to use positive register operands to
access parameter values.
Adds a Register class to keep register usage typesafe and simplify the
convertion to bytecode operand values.
BUG=v8:4280
LOG=N
Review URL: https://codereview.chromium.org/1283313003
Cr-Commit-Position: refs/heads/master@{#30151}
