optimize: optimize the speed of buildLockKey

[caohdgege]

Ⅰ. Describe what this PR did

// K为主键个数(getTableMeta().getPrimaryKeyOnlyName().size())
// M为字段数(getTableMeta().getAllColumns().size())
// N为行数(pksRows.size())

// 原复杂度
// N * M * K

// 优化后复杂度
// N * K

Ⅱ. Does this pull request fix one issue?

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[funky-eyes]

LGTM

[codecov-commenter]

Codecov Report

Merging #3700 (da4cabc) into develop (c3a441c) will increase coverage by 0.00%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##             develop    #3700   +/-   ##
==========================================
  Coverage      51.92%   51.93%           
  Complexity      3503     3503           
==========================================
  Files            639      639           
  Lines          21182    21184    +2     
  Branches        2634     2634           
==========================================
+ Hits           10999    11001    +2     
  Misses          9089     9089           
  Partials        1094     1094           

Impacted Files	Coverage Δ	Complexity Δ
.../rm/datasource/exec/mysql/MySQLInsertExecutor.java	69.41% <0.00%> (ø)	16.00 <0.00> (ø)
...urce/exec/postgresql/PostgresqlInsertExecutor.java	43.75% <20.00%> (ø)	4.00 <0.00> (ø)
...m/datasource/exec/oracle/OracleInsertExecutor.java	62.50% <50.00%> (ø)	5.00 <0.00> (ø)
.../rm/datasource/exec/BaseTransactionalExecutor.java	59.09% <100.00%> (+0.31%)	27.00 <0.00> (ø)
...o/seata/rm/datasource/sql/struct/TableRecords.java	75.26% <100.00%> (+0.26%)	21.00 <0.00> (ø)

[xingfudeshi]

LGTM.