jax.numpy: make standard input utilities respect __jax_array__

[jakevdp]

This will be important because currently, __jax_array__ is handled by many NumPy APIs as a side-effect of it being handled in the JIT abstractification pass, but in the future we will likely remove this handling.

Before:

$ JAX_DISABLE_JIT=true pytest -n auto tests/array_extensibility_test.py
...
===================== 168 failed, 134 passed in 10.04s =====================

After:

$ JAX_DISABLE_JIT=true pytest -n auto tests/array_extensibility_test.py
...
====================== 87 failed, 215 passed in 9.40s ======================