Allow numeric literals to be checked for a decimal point.

Allow numeric literals to be checked for a decimal point.

The asm.js spec decides the type of numeric literals in several places
based on if they contain a ".".
http://asmjs.org/spec/latest/

Adding methods so that AST Literals can be checked for containg a dot.

Adding a cctest that this information is available.

LOG=N
BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=test-parsing
R=rossberg@chromium.org,titzer@chromium.org

Review URL: https://codereview.chromium.org/1201783003

Cr-Commit-Position: refs/heads/master@{#29395}