[HLSL] Support element-wise matrix comparison operators

[farzonl]

Problem

Clang does not support HLSL comparison operators when either operand is a matrix.

The following operators should perform element-wise comparisons:

• <
• >
• <=
• >=
• ==
• !=

Test cases

bool2x2 matrix_matrix(float2x2 a, float2x2 b) {
  return a < b;
}

bool2x2 matrix_scalar(float2x2 a, float b) {
  return a == b;
}

bool2x2 scalar_matrix(float a, float2x2 b) {
  return a >= b;
}

Requirments

Matrix comparisons should be element-wise and produce a Boolean matrix with the same dimensions as the matrix operand.
Scalar operands should be converted to the matrix element type and broadcast across the matrix.

[farzonl]

Marking this critical as it is blocking the step matrix implementation. Will start work immediately.

[farzonl]

It doesn't look like a ton of work. Largely just need to copy exactly what vectors do.