Eagerly set arguments_, new_target_ and ths_function_ Scope, and unset if we don't need to allocate them.

This probably slightly speeds up AllocateParameterLocals, but more importantly it removes ast_value_factory_ uses. If we get rid of ast_value_factory from Scope it's easier to lazily allocate it later from within a ScopeState object.

BUG=v8:5209

Review-Url: https://codereview.chromium.org/2158333002
Cr-Commit-Position: refs/heads/master@{#37868}