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

- ExpressionFromIdentifier
- ExpressionFromLiteral
- ExpressionFromString
- FunctionSentExpression
- GetNextSymbol
- GetNumberAsSymbol
- GetSymbol
- NewExpressionList
- NewPropertyList
- NewStatementList
- NewSuperCallReference
- NewSuperPropertyReference
- NewTargetExpression
- ThisExpression

Also, the method GetIterator is specific only to the parser and is
removed from the preparser's implementation.

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

Review-Url: https://codereview.chromium.org/2274113002
Cr-Commit-Position: refs/heads/master@{#38890}