[Bug] Comparison between UInt and Int fails on GlslEs300

[thargy]

When compiling code such as

    uint index = 3;
    if (index >= 2)
        return ;

Against the GlslEs300 backend, the following error occurs (from glslangvalidator:

'>=' : wrong operand types: no operation '>=' exists that takes a left-hand operand of type ' temp mediump uint' and a right operand of type ' const int' (or there is no acceptable conversion)

This implies we need add am explicit cast in this scenario for this specific backend (compilation succeeds on other backends, can't test Metal).

[mellinoe]

GLSL ES has been a major pain with how it handles signed-unsigned and other cross-type comparisons. It's far more strict than all of the other language targets, for whatever reason.