* uops const fold rules to prevent tautological compare warnings
`bool < false` is false, `true < bool` is false, `a == a` is true, `a != a` is false
* not true for nan
* and nan does not work with llvm
* full truth table test
* revert a==a
* comments and indents
* don't call contiguous for unpadded const into multi tensor
fixed multi const folding for sharded const.
still wip, need to be careful that this does not break multi device cache somewhere
* ehh need a memory test for that
* simple sharded memory test
* fix _to_const_val and const folding around it
is_unrealized_contiguous_const is too strict and almost never hit if const is expanded.
suffice to check if there's no pad
* that test is folded
* test_const_folding
chenyu
geohotstan