fix(tianmu): fix endless loop occurs during data_cache (#1352)

[adofsauron]

1. The CACHE_ITEM type does not recurse by making a direct comparison
2. When two referenced variables have the same address,
    they are considered to be the same value

Summary about this PR

Issue Number: close #1352

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 has no change and project coverage change: +0.02 🎉

Comparison is base (7e3d1cd) 43.12% compared to head (91705f0) 43.14%.

❗ Current head 91705f0 differs from pull request most recent head f31b760. Consider uploading reports for the commit f31b760 to get more accurate results

Additional details and impacted files

@@                 Coverage Diff                 @@
##           stonedb-5.7-dev    #1353      +/-   ##
===================================================
+ Coverage            43.12%   43.14%   +0.02%     
===================================================
  Files                 1830     1830              
  Lines               396395   396392       -3     
===================================================
+ Hits                170935   171020      +85     
+ Misses              225460   225372      -88     

Impacted Files	Coverage Δ
storage/tianmu/core/mysql_expression.cpp	86.73% <0.00%> (-0.14%)	⬇️
storage/tianmu/compress/range_code.h	73.45% <0.00%> (-1.10%)	⬇️
storage/innobase/os/os0event.cc	78.01% <0.00%> (-0.71%)	⬇️
storage/tianmu/compress/top_bit_dict.cpp	66.15% <0.00%> (-0.66%)	⬇️
storage/innobase/btr/btr0sea.cc	74.81% <0.00%> (-0.37%)	⬇️
storage/perfschema/pfs_instr.cc	63.26% <0.00%> (-0.25%)	⬇️
storage/innobase/row/row0sel.cc	63.25% <0.00%> (-0.18%)	⬇️
strings/str2int.c	78.78% <0.00%> (ø)
storage/innobase/include/ib0mutex.h	71.82% <0.00%> (ø)
... and 21 more

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[hustjieke]

LGTM