[Win32] Remove obsolete fallback for drawing text without GDI+

[HeikoKlare]

❗This is an experimental PR to test if the current "fallback" logic is actually obsolete.

A check in GC.drawText() make the implementation fall back to the text rendering based on glyphs and their positions calculated by GDI even when GDI+ is used in all cases except when it contains specific characters that GDI cannot handle. This was necessary more than a decade ago because specific Chinese characters were not properly rendered by GDI+. But this is quite non-intuitive as in case GDI+/advance mode is enabled the consumer will usually expected GDI+ to be used for rendering. In addition, the problematic scenario from back then works fine now.

This change thus adapts the GC.drawText() implementation to use plain GDI+ whenever it is enabled and removes all existing fallback code. It also adds a case for not drawing line delimiters when an according style flag is set, which was not considered by the GDI+ implementation yet.

May fix #3091

[github-actions]

Test Results (win32)

   34 files  ±0     34 suites  ±0   4m 53s ⏱️ -56s
4 650 tests ±0  4 577 ✅ ±0  73 💤 ±0  0 ❌ ±0 
  174 runs  ±0    171 ✅ ±0   3 💤 ±0  0 ❌ ±0 

Results for commit 6ff4768. ± Comparison against base commit 2d4d435.

♻️ This comment has been updated with latest results.

[HeikoKlare]

Interestingly, this change would also have an impact on some issues reported to GEF (@ptziegler fyi).

It seems like the following fix would be come obsolete as I see the behavior also fixed with this PR:

• [Win32] Fix incorrect font scaling when Transform is used eclipse-gef/gef-classic#963

Without this change on 150% monitor:

With this change on 150% monitor:

For the underlying issue and the snippet posted there, I rather see a change that I would consider a regression caused by this PR:

• SWTGraphic scaling inconsistent across platforms eclipse-gef/gef-classic#945

This is how it looks without this change on 100%:

And this is how it looks with this change on 100%:

But comparing the position of the text on 100% monitor with its position on 150% monitor, the behavior after this change seems to be even more "correct".

Anyway, it seems like the Win32 GC.drawText() implementation has some severe flaws when using advanced mode / GDI+. I am just a bit afraid that simply removing all the code for falling back to GDI and completely relying on GDI+ for all text rendering when advanced mode is enabled may have unintended side effects. But checking some of the bugs for which this implementation has been made (such as https://bugs.eclipse.org/bugs/show_bug.cgi?id=289244 and https://bugs.eclipse.org/bugs/show_bug.cgi?id=305815) and running the snippets used back then without any issues after this change, hopefully GDI+ was improved so much throughout the years that all these workarounds are not necessary anymore.