fix(common): add unit test for --debug flag for builder

[mcdurdin]

Fixes #10957. The builder --debug flag appears to be passed correctly, according to this test. This is a good test to keep, so won't remove it, but there is something else going on in the base #10953 PR.

@keymanapp-test-bot skip

[keymanapp-test-bot[bot]]

User Test Results

Test specification and instructions

User tests are not required

Test Artifacts

• Android
  • Keyman for Android apk
  • FirstVoices for Android 16.0 apk
  • FirstVoices Keyboards for Android apk
  • KeyboardHarness apk
  • Keyman for Android 16.0 apk
  • KMSample1 apk
  • KMSample2 apk
• Developer
  • Keyman Developer
  • Compiler Regression Tests
  • kmcomp.zip
• iOS
  • Keyman for iOS (simulator image)
  • FirstVoices Keyboards for iOS (simulator image)
  • TestFlight internal PR build version - 17.0.286 (0.10974.10552)
• Keyboards
  • Test Keyboards
• Linux
  • Keyman for Linux: focal
  • Keyman for Linux: jammy
  • Keyman for Linux: mantic
  • Keyman for Linux: noble
• macOS
  • Keyman for macOS
• Web
  • KeymanWeb Test Home
• Windows
  • Keyman for Windows
  • FirstVoices Keyboards for Windows
  • Text Editor (32 bit)
  • Text Editor (64 bit)

[keyman-server]

Changes in this pull request will be available for download in Keyman version 17.0.289-beta