453446 Disable fixSWT workaround for SWT >= 3.104 (Mars)

- No longer needed now that the SWT host takes care of pulling in the
  right implementation fragment (cf. bug 361901).
- Fix some warnings.

Bug: 453446
Bug: 361901
Change-Id: I3b8bbc58caf3dd63f61d0ca382cd19810e152720