Add `cl_ext_immutable_memory_objects` tests writing to and from buffer

[MichaelRizkalla-arm]

This change extends the test coverage for https://github.com/KhronosGroup/OpenCL-Docs/pull/1280

The change tests:

1. Writing to immutable buffers.
2. Writing to buffer/image from immutable buffers.
3. Reading from immutable buffers.

This change adds the following tests:

1. test_negative_imagearraycopy
2. test_negative_imagearraycopy3d
3. test_immutable_bufferreadwriterect
4. test_immutable_arrayreadwrite
5. test_write_from_immutable_buffer_to_buffer
6. test_immutable_buffer_map_*

and extends the following tests:

1. test_arrayimagecopy3d
2. test_arrayimagecopy
3. test_imagearraycopy3d
4. test_imagearraycopy
5. test_buffer_copy
6. test_buffer_partial_copy