Fixed interval type null/missing check failure

[chloe-zh]

Issue #, if available:
#991

Description of changes:

• Interval type failed semantic check in aggregations with implicit group by, so added interval type as literal type to be non-aggregation select items to pass the check
• Handled null and missing value check for interval type
• Added corresponding tests. Note: didn't add comparison test because missing INTERVAL in JDBC types

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Merging #1011 (f31672b) into develop (1101df0) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@              Coverage Diff              @@
##             develop    #1011      +/-   ##
=============================================
- Coverage      99.87%   99.87%   -0.01%     
+ Complexity      2406     2403       -3     
=============================================
  Files            234      234              
  Lines           5526     5520       -6     
  Branches         357      357              
=============================================
- Hits            5519     5513       -6     
  Misses             5        5              
  Partials           2        2              

Impacted Files	Coverage Δ	Complexity Δ
...search/sql/expression/datetime/IntervalClause.java	100.00% <100.00%> (ø)	21.00 <0.00> (ø)
...icsearch/sql/sql/parser/AstAggregationBuilder.java	100.00% <100.00%> (ø)	14.00 <4.00> (-3.00)

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[dai-chen]

Thanks for the fix!

[penghuo]

LGTM