Always propagate exceptions in DAP

This changes the DAP exec_and_log function to always transform an
exception into a DAPException and propagate it.

As the bug points out, we haven't always wrapped calls when
appropriate.  I think it's better to cause the request to fail by
default; if any spot truly needs to ignore errors, that is readily
done at the point of call.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=33346