fix: ACNA-2422 - consolidate token-helper test files into one

[shazron]

closes #136

How Has This Been Tested?

npm test

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #138 (dadbf24) into master (bd36954) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #138   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            9         9           
  Lines          489       488    -1     
  Branches        69        68    -1     
=========================================
- Hits           489       488    -1     

Files Changed	Coverage Δ
src/token-helper.js	100.00% <100.00%> (ø)

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