fix: Concurrent Modification Exception

[ebhsgit]

Fix for #924

Platforms affected

Android

Motivation and Context

ConcurrentModificationException occurs when starting app, and sometimes randomly in app usage

Description

Use Collection.synchronizedMap and ensure all access is sync by wrap all usage of the collection with synchronized keyword

Testing

Used for a few months in production now without any issues

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• I've updated the documentation if necessary

[codecov-io]

Codecov Report

Merging #1091 into master will increase coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1091      +/-   ##
==========================================
+ Coverage   69.71%   69.76%   +0.05%     
==========================================
  Files          20       20              
  Lines        1806     1806              
==========================================
+ Hits         1259     1260       +1     
+ Misses        547      546       -1     

Impacted Files	Coverage Δ
bin/templates/cordova/lib/check_reqs.js	59.43% <0.00%> (+0.47%)	⬆️

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[breautek]

Thank you for your contribution @ebhsgit