test_enqueued_local_size should be redesigned

The test as it is relies on the fact that `num_elements` is not a multiple of 3 hard-coded numbers to be valid. It tests a single set of values and doesn't take into account the device limits when picking workgroup sizes for the test. It should be revised.

See https://github.com/KhronosGroup/OpenCL-CTS/pull/414.

Locate the test_enqueued_local_size test and read the discussion in OpenCL-CTS pull request 414 first. Review how its hard-coded values depend on num_elements and how device workgroup limits are exposed. Done means the test covers more than one value set without assuming invalid sizes for the device.

Written by the indexing model from the issue text.