Fix OpenGL ES type issues in ACES2 FixedFunction Ops

[remia]

Address #2269

[KevinJW]

Have not looked at the exact code this now emits, but when I looked at the original issue, I did wonder about the code in the cusp table ...

  int i_lo = int(max(float(0), float(i + 0)));
  int i_hi = int(min(float(361), float(i + 2)));

The original blink/c++/etc assumed integer division properties when doing the binary search so used integer types. I guess we'll need to check carefully about all these type conversions and the available function support under the various shader languages.

[remia]

Just double checked with the OpenGL ES tests I'm running, all tests pass successfully provided I'm using the following defaults precision qualifier (without this almost everything fails).

precision highp float;
precision highp int;
precision highp sampler2D;
precision highp sampler3D;