Resolve resources URLs as file-URLs if running in an OSGi environment

[HannesWell]

Don't consider the 'PLUGIN_PATH' property anymore, which is set in I-build tests and whose handling doesn't work anymore.

Fixes #2001 (hopefully).

[github-actions]

Test Results

   539 files   -  6     539 suites   - 6   31m 17s ⏱️ + 3m 25s
 4 336 tests  - 37   4 326 ✅  - 35    9 💤  - 3  1 ❌ +1 
16 597 runs   - 37  16 495 ✅  - 35  101 💤  - 3  1 ❌ +1 

For more details on these failures, see this check.

Results for commit 44c66fc. ± Comparison against base commit f468eca.

This pull request removes 37 tests.

AllWin32Tests org.eclipse.swt.graphics.ImageWin32Tests ‑ testImageDataForDifferentFractionalZoomsShouldBeDifferent
AllWin32Tests org.eclipse.swt.graphics.ImageWin32Tests ‑ testImageShouldHaveDimesionAsPerZoomLevel
AllWin32Tests org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testByteArrayTransfer
AllWin32Tests org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testFileTransfer
AllWin32Tests org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testHtmlTransfer
AllWin32Tests org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testImageTransfer_fromCopiedImage
AllWin32Tests org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testImageTransfer_fromImage
AllWin32Tests org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testImageTransfer_fromImageData
AllWin32Tests org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testImageTransfer_fromImageDataFromImage
AllWin32Tests org.eclipse.swt.tests.win32.Test_org_eclipse_swt_dnd_DND ‑ testRtfTransfer
…

♻️ This comment has been updated with latest results.

[HeikoKlare]

Is it good to add an Equinox dependency to the SWT tests? I find that a bit strange since those tests are (outside of an I-Build) executed as plain JUnit tests without any OSGi environment.

In case this is reasonable, we should probably remove the PLUGIN_PATH property from the build scripts, as that one is only used for the SWT tests, isn't it?

[HannesWell]

Is it good to add an Equinox dependency to the SWT tests? I find that a bit strange since those tests are (outside of an I-Build) executed as plain JUnit tests without any OSGi environment.

That was indeed not ideal and I just used that since avoiding it seemed cumbersome and it worked in all cases (by chance) as described initially because the class-loader then already returned file URLs.
But I tried it again and turned out to not be that complicated eventually.

In case this is reasonable, we should probably remove the PLUGIN_PATH property from the build scripts, as that one is only used for the SWT tests, isn't it?

Good point. I checked all the SDK git repos and didn't found another use of that property. So I think we can remove it. I'll create a follow up in the platform.releng.aggregator repo once we have a confirmation that these tests work again.

[HannesWell]

In case this is reasonable, we should probably remove the PLUGIN_PATH property from the build scripts, as that one is only used for the SWT tests, isn't it?

For the record, see eclipse-platform/eclipse.platform.releng.aggregator#2989.