airframe-http: #1128 Add Router.verifyRoutes to check duplicated endpoints

[xerial]

Because of the complexity of mapping RPC functions to HTTP endpoints, we should avoid using method overload (e.g., def m(p1), def m(p1, p2,...)). The current behavior is IllegalArgumentException is thrown when Router is used for building HTTP filters.

This PR adds Router.verifyRoutes so that we can manually find the presence of method overload early.

[codecov]

Codecov Report

Merging #1137 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1137   +/-   ##
=======================================
  Coverage   82.57%   82.57%           
=======================================
  Files         276      276           
  Lines       10544    10545    +1     
  Branches      641      673   +32     
=======================================
+ Hits         8707     8708    +1     
  Misses       1837     1837           

Impacted Files	Coverage Δ
...vm/src/main/scala/wvlet/airframe/http/Router.scala	87.30% <100.00%> (+0.20%)	⬆️
...ala/wvlet/airframe/http/codegen/RouteScanner.scala	40.00% <100.00%> (+3.15%)	⬆️
...shared/src/main/scala/wvlet/log/io/StopWatch.scala	80.00% <0.00%> (-0.21%)	⬇️

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[takezoe]

Worked as expected. Thanks for adding this!