Split out from cl/8024 for clarity and improved approach.
Rarely, "stop reason = breakpoint" does not appear in the lldb stop
text. However the program is ready to proceed. To be a little more
robust about those cases, we wait for two seconds, and if that text
doesn't appear but a prompt does we continue and hope for the best.
Worst case, this results in a harder to read failure message.
Change-Id: Ib20aa92564cdccefd2b7260417c647cd44122b66
Reviewed-on: https://go-review.googlesource.com/8080 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>