Always use full-named launcher library native fragment on Mac

[HannesWell]

For all supported platforms full-named native launcher fragments exist with name 'org.eclipse.equinox.launcher...' for a long time, even for all architectures supported on mac.

Also remove consideration of old development locations of the launcher fragments.

As a side-effect, this also fixes https://github.com/eclipse-equinox/equinox/issues/625.

[github-actions[bot]]

Test Results

  660 files  ±0    660 suites  ±0   1h 10m 26s :stopwatch: - 2m 25s 2 195 tests ±0  2 148 :white_check_mark: ±0   47 :zzz: ±0  0 :x: ±0  6 729 runs  ±0  6 586 :white_check_mark: ±0  143 :zzz: ±0  0 :x: ±0 

Results for commit 51b7266e. ± Comparison against base commit fadf6d11.