Make hasNext idempotent as a workaround for https://github.com/scala/bug/issues/11453

[xerial]

No description provided.

[codecov]

Codecov Report

Merging #471 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #471      +/-   ##
=========================================
+ Coverage   83.09%   83.1%   +<.01%     
=========================================
  Files         181     181              
  Lines        7240    7244       +4     
  Branches      687     687              
=========================================
+ Hits         6016    6020       +4     
  Misses       1224    1224

Impacted Files	Coverage Δ
...rc/main/scala/wvlet/airframe/codec/JDBCCodec.scala	86.36% <100%> (+0.36%)	⬆️

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