import test dependencies from testArtifacts rather than archives.

[p-s-dev]

Building always worked from the command line. However, IntelliJ refused to accept the "archives" configuration as a valid source for test dependencies. By defining a new configuration "testArtifacts" and exporting it from the subprojects that contain shared test classes, I'm able to open the project in IntelliJ and compile it with no "can not find symbol" errors in the cross-project imports.

Also Removed a duplicate TempFileProvider class and change to dependency reference.

[codecov]

Codecov Report

Merging #455 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #455      +/-   ##
============================================
+ Coverage      76.6%   76.61%   +0.01%     
- Complexity     1635     1636       +1     
============================================
  Files           215      215              
  Lines          6129     6129              
  Branches        961      961              
============================================
+ Hits           4695     4696       +1     
  Misses         1203     1203              
+ Partials        231      230       -1

Impacted Files	Coverage Δ	Complexity Δ
...ore/src/main/java/org/web3j/utils/Observables.java	84% <0%> (+4%)	10% <0%> (+1%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d53933e...267fef9. Read the comment docs.

[conor10]

Thanks! 👍