fix(build): Allow platform args with double dash

[dpogue]

Platforms affected

iOS

Motivation and Context

The Cordova docs say to provide platform-specific arguments after a -- on the CLI. Currently this works on Android, but does not work for iOS.

Closes GH-1488.

Description

Ensure that we parse any extra (platform-specific) arguments passed from cordova-cli in to the iOS build command through options.argv. These are arguments that are provided after a -- to the CLI command.

There is no change for existing arguments passed without the double dash.

The priority of arguments is now:

1. Platform-specific arguments passed after a double-dash.
2. Arguments passed without a double-dash (current behaviour).
3. Values provided in a build.json config file.

Testing

Added unit tests to cover argument parsing and fallback behaviour.

Checklist

• I've run the tests to see all new and existing tests pass
• I added automated test coverage as appropriate for this change
• 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)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 80.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 81.34%. Comparing base (3737f51) to head (b81f3c5).

Files with missing lines	Patch %	Lines
lib/build.js	80.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1516      +/-   ##
==========================================
+ Coverage   80.84%   81.34%   +0.50%     
==========================================
  Files          16       16              
  Lines        1848     1855       +7     
==========================================
+ Hits         1494     1509      +15     
+ Misses        354      346       -8     

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[erisu]

LGTM

Tested command while passing in buildFlag.

• Before --
• After --
• Before and After --
  • Arguments after -- are used. Before will be dropped as expected.
• Before -- with build.json
  • Arguments in build.json are dropped in favor for CLI args. No merging.
• After -- with build.json
  • Arguments in build.json are dropped in favor for CLI args. No merging.
• build.json only