Continue label incorrectly allowed to be a non-IterationStatement label

Filed by @michaelficarra previously as issue 450.

What steps will reproduce the problem?

Attempt to parse for(;;){ a: continue a; }.

What is the expected output?

The parse should fail to parse the program.

What do you see instead?

The parser allows the illegal continue.

What version of the product are you using? On what operating system? Which browser?

esprima master on node v0.10.15

Please provide any additional information below.

See ES5 section 12.7, specifically "A program is considered syntactically incorrect if [...] The program contains a continue statement with the optional Identifier, where Identifier does not appear in the label set of an enclosing (but not crossing function boundaries) IterationStatement.", as opposed to section 12.8 (break) which states "A program is considered syntactically incorrect if [...] The program contains a break statement with the optional Identifier, where Identifier does not appear in the label set of an enclosing (but not crossing function boundaries) Statement.", emphasis mine.

Reproduce the parser behavior with for(;;){ a: continue a; } and inspect the parsing path for labeled continue statements. Done means the parser rejects this program while preserving the distinct label rules for continue and break described in ES5 sections 12.7 and 12.8.