NASTY ERROR in PostfixExpression-parsing!

added test case, the following expressions are LEGAL according to
grammar:
new int[3][][][6]
new int[3][][6]
new int[3][6]
new int[3][6][3]

Nastiness: ArrayAccess is a valid PostfixOp of a NewArrayExpression!
Problem: in parsePrimary (where we parse NewArrayExpression), we consume
AS MANY "[]" as possible, possibly consuming the opening bracket of an
ArrayAccess and the MISTAKENLY expecting a closing bracket to follow!
Fixed parsePrimary

...only consume brackets if there IS a closing to prevent conflict with
ArrayAccess