fix Fingerprint fi overflow cause index out of range panic

[martianzhang]

sql: insert into tb values(1)
Fingerprint(sql) got panic: index out of range

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #30 into master will decrease coverage by 0.09%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master      #30     +/-   ##
=========================================
- Coverage   63.91%   63.82%   -0.1%     
=========================================
  Files           8        8             
  Lines        1416     1418      +2     
=========================================
  Hits          905      905             
- Misses        400      401      +1     
- Partials      111      112      +1

Impacted Files	Coverage Δ
query/query.go	65.5% <0%> (-0.23%)	⬇️

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[codecov]

Codecov Report

Merging #30 into master will increase coverage by 0.04%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #30      +/-   ##
==========================================
+ Coverage   67.02%   67.07%   +0.04%     
==========================================
  Files           7        7              
  Lines        1389     1391       +2     
==========================================
+ Hits          931      933       +2     
  Misses        348      348              
  Partials      110      110

Impacted Files	Coverage Δ
query/query.go	65.91% <100%> (+0.11%)	⬆️

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[rnovikovP]

Thanks for contributing @martianzhang! Let us check this and get back to you soon

[percona-csalguero]

Without the code change, the tests are passing anyways.
I don't think we need to merge this.
In order to accept this change, I would like to see a failing case.

[martianzhang]

@percona-csalguero I update the test case, no space between values and the left bracket will raise a panic.