Fix a couple terrible optimizer bugs

Just because an expression is always true or false, doesn't mean we can
execute it more often than it otherwise would be, unless it's also pure.
But that's equivalent to being identically -true/-false, so just check
that.

1 files changed, 0 insertions, 0 deletions

diff --git a/tests/test_or_purity.out b/tests/test_or_purity.out
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/test_or_purity.out