Edge: freezes in evalute()

[HeikoKlare]

Calling evaluate() on an Edge browser freezes (until a timeout occurs) in case the evaluated script causes a callback to SWT.

See:

• Edge: Freeze in Browser#evaluate() if evaluated script calls into SWT eclipse-platform/eclipse.platform.swt#1771
• Edge: Operation timed out on evaluate() eclipse-platform/eclipse.platform.swt#1919 (comment)

[HeikoKlare]

Reopening this as the PR eclipse-platform/eclipse.platform.swt#1973 introduced a regression regarding eclipse-platform/eclipse.platform.swt#1919

Since the behavior changed from timeout to deadlock, I increase priority to urgent.