chore(sqllab): Do not strip comments when executing SQL statements

[john-bodley]

SUMMARY

I realize there is merit for stripping SQL comments when parsing SQL to extract tables etc., i.e., to aid with simplification, however I'm not entirely sure why we do this when executing SQL especially given that numerous SQL dialects supports optimizer hints in the form of comments:

• MySQL
• Spark SQL

This PR ensures when running SQL statements in SQL Lab we don't strip away the comments.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

CI.

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.85%. Comparing base (5e8459b) to head (7b317d6).
Report is 90 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #27725      +/-   ##
==========================================
+ Coverage   67.46%   69.85%   +2.38%     
==========================================
  Files        1910     1911       +1     
  Lines       74802    74988     +186     
  Branches     8345     8345              
==========================================
+ Hits        50467    52381    +1914     
+ Misses      22284    20556    -1728     
  Partials     2051     2051              

Flag	Coverage Δ
hive	48.93% <ø> (?)
mysql	77.91% <ø> (-0.12%)	⬇️
postgres	78.02% <ø> (-0.12%)	⬇️
presto	53.64% <ø> (?)
python	83.15% <ø> (+4.87%)	⬆️
sqlite	77.46% <ø> (-0.12%)	⬇️
unit	56.76% <ø> (?)

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[betodealmeida]

Oh yeah, we should definitely not be stripping comments. There are multiple reasons to leave them — in addition to optimization like you mentioned I've also seen them used for auditing. Thanks for fixing this!

[betodealmeida]

(I restarted the flaky MySQL test for you.)