Memoryview.is_c_contig() and is_f_contig() used in the same block causes `is_f_contig` to be omitted

[dhermes]

I made a repro you can check out. The issue manifests at runtime as:

undefined symbol: __pyx_memviewslice_is_f_contig2

[scoder]

Thank you for the reproducing example.

[dhermes]

Thanks for the fix!