fix(tianmu): To support union(all) the statement which is without from clause

[RingsC]

Summary about this PR

1: To fixup unsupport union or union all a sql statement which is without from clause.
2: Re-format some codes and functions.
Issue Number: close #1860

Tests Check List

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Changelog

• New Feature
• Bug Fix
• Performance Improvement
• Build/Testing/CI/CD
• Documentation
• Not for changelog (changelog entry is not required)

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features

[mergify]

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[codecov]

Codecov Report

Patch coverage: 78.80% and project coverage change: +60.27 🎉

Comparison is base (73dcfec) 0.00% compared to head (0e9ec24) 60.27%.

❗ Current head 0e9ec24 differs from pull request most recent head 9f94496. Consider uploading reports for the commit 9f94496 to get more accurate results

Additional details and impacted files

@@                 Coverage Diff                  @@
##           stonedb-5.7-dev    #1887       +/-   ##
====================================================
+ Coverage                 0   60.27%   +60.27%     
====================================================
  Files                    0     1837     +1837     
  Lines                    0   380671   +380671     
====================================================
+ Hits                     0   229466   +229466     
- Misses                   0   151205   +151205     

Impacted Files	Coverage Δ
storage/tianmu/core/just_a_table.h	100.00% <ø> (ø)
storage/tianmu/core/query_compile.cpp	65.65% <ø> (ø)
storage/tianmu/core/temp_table.h	58.33% <ø> (ø)
storage/tianmu/optimizer/compile/compiled_query.h	72.00% <ø> (ø)
storage/tianmu/sql/ha_my_tianmu.cpp	47.05% <ø> (ø)
storage/tianmu/core/engine_execute.cpp	59.38% <53.84%> (ø)
storage/tianmu/index/multi_index.h	56.66% <56.66%> (ø)
storage/tianmu/core/temp_table.cpp	74.83% <72.72%> (ø)
storage/tianmu/index/multi_index.cpp	81.45% <81.45%> (ø)
storage/tianmu/core/temp_table_com.cpp	67.85% <87.50%> (ø)
... and 5 more

... and 1822 files with indirect coverage changes

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[Nliver]

LGTM