Not equal predicate in physical_planning pruning

[jgoday]

Which issue does this PR close?

Closes #420.

Rationale for this change

Pruning not equal predicates if the value is between min and max bounds.

What changes are included in this PR?

Are there any user-facing changes?

Change datafusion/src/physical_optimizer/pruning.rs build_predicate_expression to include Operator::NotEq
and define test case 'row_group_predicate_not_eq'

[codecov-commenter]

Codecov Report

Merging #544 (c4e91d9) into master (ad70a1e) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #544      +/-   ##
==========================================
+ Coverage   76.13%   76.15%   +0.01%     
==========================================
  Files         156      156              
  Lines       27032    27047      +15     
==========================================
+ Hits        20582    20597      +15     
  Misses       6450     6450              

Impacted Files	Coverage Δ
datafusion/src/physical_optimizer/pruning.rs	92.52% <100.00%> (+0.24%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ad70a1e...c4e91d9. Read the comment docs.

[Dandandan]

LGTM 👍

[alamb]

Looks awesome -- thank you @jgoday !

[alamb]

I think we got the logic a bit too aggressive see -- see #560. FYI @jgoday