optimize: throw Exception when no index in the table

[l81893521]

Ⅰ. Describe what this PR did

git some tips when no index in the table cause NPE in TableMetaCache.java.

Ⅱ. Does this pull request fix one issue?

#1529

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

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #1530 into develop will increase coverage by 0.01%.
The diff coverage is 50%.

@@              Coverage Diff              @@
##             develop    #1530      +/-   ##
=============================================
+ Coverage      46.43%   46.44%   +0.01%     
- Complexity      1691     1692       +1     
=============================================
  Files            347      347              
  Lines          12713    12717       +4     
  Branches        1588     1590       +2     
=============================================
+ Hits            5903     5907       +4     
+ Misses          6172     6170       -2     
- Partials         638      640       +2

Impacted Files	Coverage Δ	Complexity Δ
...rm/datasource/sql/struct/TableMetaCacheOracle.java	0% <0%> (ø)	0 <0> (ø)	⬇️
...seata/rm/datasource/sql/struct/TableMetaCache.java	53.65% <100%> (+1.8%)	14 <0> (+1)	⬆️
...server/store/file/FileTransactionStoreManager.java	47.03% <0%> (-0.35%)	19% <0%> (ø)
...very/registry/zk/ZookeeperRegisterServiceImpl.java	64.56% <0%> (+0.78%)	24% <0%> (ø)	⬇️

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[slievrly]

LGTM

[xingfudeshi]

LGTM.