math_brute_force: treat reciprocal as unary function (#2281)

Treat reciprocal as a unary function, instead of handling it through the
binary function testing mechanism and special-casing it there.

This addresses two shortcomings of the previous implementation:

- Testing took significantly longer as the entire input domain was
tested many times (e.g. fp16 reciprocal has only 2^16 possible input
values, but binary function testing iterates over 2^16 * 2^16 input
values).

- The reciprocal test kernel was identical to the divide kernel. Thus
the device compiler would see a regular divide operation instead of a
reciprocal operation and would be unlikely to emit a specialized
reciprocal sequence.

This reverts all of the changes in binary_operator*.cpp made by
bcfa1f7c2 ("Added corrections to re-enable reciprocal test in
math_brute_force suite for relaxed math mode (#2221)", 2025-02-04).

Signed-off-by: Sven van Haastregt <sven.vanhaastregt@arm.com>

test_conformance/math_brute_force/unary_float.cpp

@@ -28,7 +28,12 @@ cl_int BuildKernelFn(cl_uint job_id, cl_uint thread_id UNUSED, void *p)
     BuildKernelInfo &info = *(BuildKernelInfo *)p;
     auto generator = [](const std::string &kernel_name, const char *builtin,
                         cl_uint vector_size_index) {
-        return GetUnaryKernel(kernel_name, builtin, ParameterType::Float,
+        const char *builtinCall = builtin;
+        if (strcmp(builtin, "reciprocal") == 0)
+        {
+            builtinCall = "((RETTYPE)(1.0f))/";
+        }
+        return GetUnaryKernel(kernel_name, builtinCall, ParameterType::Float,
                               ParameterType::Float, vector_size_index);
     };
     return BuildKernels(info, job_id, generator);