Add MaxInt tests to gl-uniform-arrays.html

Add tests to gl-uniform-arrays.html that ensure there is no overflow when calling
getUniformLocation with an array uniform that has an index greater than or equal
to MaxInt.

For instance, 'gl.getUniformLocation(program, "myuniform[4294967296]")' should
fail.
Address feedback from @zhenyao

The MaxInt variable in the test has an confusing name for a couple of reasons:
1) The maximum integer that JS can safely handle is 2^53.
2) The maximum 32 bit integer is 2^32-1, not 2^32.

Renamed MaxInt variable to MaxInt32PlusOne.  The 32 clarifies we want the maximum 32 bit integer.
PlusOne indicates we want 2^32, which will trigger the overflow condition.
Merge pull request #775 from RafaelCintron/maxIntUniformArrayIndexing

Add MaxInt tests to gl-uniform-arrays.html