Shared environment arena config

[yuzawa-san]

Description of Changes

• configure a shared arena for CPU allocator on the environment

[codecov]

Codecov Report

Merging #123 (dd0ca1a) into master (ac5b327) will increase coverage by 0.25%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master     #123      +/-   ##
============================================
+ Coverage     80.27%   80.53%   +0.25%     
- Complexity      318      321       +3     
============================================
  Files            49       49              
  Lines          1359     1377      +18     
  Branches         84       86       +2     
============================================
+ Hits           1091     1109      +18     
  Misses          233      233              
  Partials         35       35              

Impacted Files	Coverage Δ
...main/java/com/jyuzawa/onnxruntime/OnnxRuntime.java	100.00% <ø> (ø)
src/main/java/com/jyuzawa/onnxruntime/Session.java	0.00% <ø> (ø)
src/main/java/com/jyuzawa/onnxruntime/ApiImpl.java	97.71% <100.00%> (+0.02%)	⬆️
.../java/com/jyuzawa/onnxruntime/EnvironmentImpl.java	87.01% <100.00%> (+3.40%)	⬆️