continue(1) and break(1) should not be syntax errors

[sunverwerth]

The optional numeric constant for break and continue statements can be enclosed in parentheses which is erroneously reported as a syntax error:

';' expected.

See here: http://sandbox.onlinephpfunctions.com/code/19bee6f4f7dc93a6a146950fd9877a438c131897

[roblourens]

http://php.net/manual/en/control-structures.continue.php

[mousetraps]

Would also be good to update the language spec

https://github.com/php/php-langspec/blob/master/spec/19-grammar.md#grammar-continue-statement

[sunverwerth]

Just opened a pull request at php-langspec: php/php-langspec#211