[v9_16] Make sure .txt files are not identified as crashed test

Previously .txt files with full backtrace may be identified as a crashed test:

I:Core dumps were found for the following system tests:
I:	 core.19948-backtrace.txt
I:   shutdown

Now .txt files are removed from the list.

Change 'run.sh.in' to match the core matching pattern in 'testsummary.sh'.

(cherry picked from commit c2dcd959)