Debug time graph verification

[zcbenz]

Add debug time check that would throws error when 2 common types of errors are found:

1. Temporary arrays are not registered by add_temporary

This is checked by iterating all pointers in the graph and checking whether they are valid allocations, which can capture mistakes like the ones fixed by #4660:

Traceback (most recent call last):
  File "/Users/zcbenz/codes/mlx/python/tests/test_fast_gated_delta.py", line 317, in run
    mx.eval(outs, vjps)
    ~~~~~~~^^^^^^^^^^^^
RuntimeError: There are invalid memory registered when calling GatedDeltaUpdateVJP::eval_gpu, which is a bug that corrupts the graph, and usually caused by temporary arrays not registered with "add_temporray" method.

2. Input or outputs arrays are accidentally registered by add_temporary

This is checked by simply checking whether the temporaries contain inputs or outputs of a primitive, which can capture mistakes like the ones fixed by #4702:

Traceback (most recent call last):
  File "/Users/zcbenz/codes/mlx/issue.py", line 17, in <module>
    mx.eval(mx.array_equal(g, expected))
    ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RuntimeError: A output of array is registered as temporary when calling CrossEntropyVJP::eval_gpu, which is a bug that corrupts the graph.