Allow paren-wrapped function literals with `immed`

Function literals must be wrapped in parenthesis if their properties are
to be accessed. Ensure that this syntax does not trigger warnings when
the `immed` option is set.

The native Function prototype may be extended with any arbitrary
property, making the current property whitelisting approach
inappropriate.

Closes gh-1737
v2.5.6
Parse ES6 ComputedPropertyNames. Fixes gh-1845

Closes #1846
Merge pull request #1843 from jugglinmike/1737-immed-expr

Allow paren-wrapped function literals with `immed`
Add additional ignoreDelimiter code to fixture
Comments are ignored inside ignore start/end. Closes gh-1855
Test for punctuator tokens in lookupBlockType. Fixes gh-1856

Closes #1857
Don't issue W088 if identifier is declared in a higher scope

Closes #1016
Closes #1860