This patch moves the following methods from the traits objects to
the (pre)parser implementation objects:

- BuildIteratorResult
- BuildUnaryExpression
- EmptyExpression
- EmptyFunctionLiteral
- EmptyIdentifier
- EmptyIdentifierString
- EmptyLiteral
- EmptyObjectLiteralProperty
- GetLiteralTheHole
- NewThrowReferenceError
- NewThrowSyntaxError
- NewThrowTypeError
- NullExpressionList
- ReportMessageAt

R=adamk@chromium.org, marja@chromium.org
BUG=
LOG=N

Review-Url: https://codereview.chromium.org/2268413002
Cr-Commit-Position: refs/heads/master@{#38862}