Removed code for unsupported pack-unpack language.

Review URL: https://codereview.appspot.com/9685045

git-svn-id: http://angleproject.googlecode.com/svn/trunk@2246 736b8ea6-26fd-11df-bfd4-992fa37f6226
Removed checks for zero-length arrays because you can never define such arrays.
Also removed support for max-array-size. You can only define a fixed-size array.

TEST=WebGL conformance tests

Review URL: https://codereview.appspot.com/9697044

git-svn-id: http://angleproject.googlecode.com/svn/trunk@2247 736b8ea6-26fd-11df-bfd4-992fa37f6226