Pretend VM resume succeeded once after a thread termination.

Otherwise MonoDevelop 2.8.8.4 produces lots of annoying
message boxes about exceptions because of earlier commit
5775c9f548cd5702ca1da10872f3b0a92f92f6e8.
Fix single step mode logging in debuger agent.
Emit the post-call single-step sequence points even with debug info.

They are critical for Step Out in a statement with multiple calls.