fix: pass immutable arg_id_to_dtype to InKernelCallables

examples/python/call-external.py

loopy/kernel/function_interface.py

loopy/library/function.py

loopy/library/random123.py

loopy/library/reduction.py

loopy/target/c/__init__.py

loopy/target/opencl.py

loopy/target/pyopencl.py

test/library_for_test.py

test/testlib.py