cpcloud BUG: Fix equality
Closes #1599  This is a temporary fix that preserves most existing
behavior until we can refactor the compiler to separate compilation
from optimization.

Author: Phillip Cloud <cpcloud@gmail.com>

Closes #1600 from cpcloud/fix-equality and squashes the following commits:

92f9cbf [Phillip Cloud] Revert and use compat zip
05bab25 [Phillip Cloud] Rename compare_argument_sequences to empty_or_equal
346114b [Phillip Cloud] Clean up code
e83a5ea [Phillip Cloud] Xfail on newly broken test
9334c23 [Phillip Cloud] Fix notebook
75e8b65 [Phillip Cloud] Flake8
2b0ceba [Phillip Cloud] BUG: Fix equality
Latest commit 591c058 Sep 6, 2018