The following tests under `spirv_new`:
* `op_branch_conditional`
* `op_phi`
* `op_selection_merge`
were using randomly generated `cl_int` values, and storing the
difference between them as a `cl_int`. If one of the generated values is
negative and large enough, while the other is positive and large enough,
the difference then becomes a larger value that cannot be represented
using `cl_int`.
Switch the tests to use `cl_uint` instead, and update the relevant
spvasm{32,64} files to use `OpULessThan` instead of `OpSLessThan`.
Signed-off-by: Ahmed Hesham <ahmed.hesham@arm.com>
5d85fb3e3b