Modified returning NaN to NULL

[GumpacG]

Signed-off-by: Guian Gumpac guian.gumpac@improving.com

Description

Modified ln, log, log10, and log2 functions to return null when the Math functions return NaN.

Issues Resolved

opensearch-project#1280

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Merging #225 (5be477e) into integ-fix-nan-bug (e990201) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@                 Coverage Diff                  @@
##             integ-fix-nan-bug     #225   +/-   ##
====================================================
  Coverage                98.36%   98.36%           
- Complexity                3636     3642    +6     
====================================================
  Files                      343      343           
  Lines                     8990     8995    +5     
  Branches                   585      585           
====================================================
+ Hits                      8843     8848    +5     
  Misses                     142      142           
  Partials                     5        5           

Flag	Coverage Δ
sql-engine	98.36% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
...ssion/operator/arthmetic/MathematicalFunction.java	100.00% <100.00%> (ø)

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