Use the existing image to initialize the GC in ImageGcDrawerWrapper

[ShahzaibIbrahim]

In ImageGCDrawerWrapper#newImageHandle, we create a new image with existing data to initialize the GC, instead we could use the existing image object and the base handle should be created as it is done in PlainImageDataProvider.

[github-actions]

Test Results

   484 files   -    62     484 suites   - 62   23m 56s ⏱️ - 8m 54s
 4 334 tests  -    91   4 321 ✅  -    87   12 💤  -  5  1 ❌ +1 
13 069 runs   - 3 677  12 952 ✅  - 3 667  116 💤  - 11  1 ❌ +1 

For more details on these failures, see this check.

Results for commit 099e31c. ± Comparison against base commit d4c3036.

This pull request removes 91 tests.

AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicASCII_dollarSign
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicASCII_emptyString
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicASCII_letterA
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicASCII_letters
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicUTF16LE_null
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicUTF16_AsciiLetters
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicUTF16_Asciiletter
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicUTF16_LotsOfLetters
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicUTF16_letter
AllGTKTests org.eclipse.swt.tests.gtk.Test_GtkConverter ‑ test_HeuristicUTF16_letters
…

♻️ This comment has been updated with latest results.

[HeikoKlare]

I've tested the behavior with the LineNumberRuler and that seems to be work fine with different zooms. But with this change we will see the following warnings when strict checks are enabled, which need to be resolved:

***WARNING: Images with handles created for multiple zooms should not be modified.  It should be created with an ImageGcDrawer (see SWT Snippet 384).

[HeikoKlare]

Is this something we can only do for the Windows implementation or may we adapt all the MacOS and Linux implementations of Image as well?

[ShahzaibIbrahim]

***WARNING: Images with handles created for multiple zooms should not be modified. It should be created with an ImageGcDrawer (see SWT Snippet 384).

This error should go away once this PR is merged.

[ShahzaibIbrahim]

Is this something we can only do for the Windows implementation or may we adapt all the MacOS and Linux implementations of Image as well?

Yes, it make sense to adapt the MacOS and Linux implementation of Image. But since I can't test the changes, I will wait until @fedejeanne is back and can test those changes with him.