[gdb/testsuite] Fix gdb.gdb/selftest.exp regexp
With gdb.gdb/selftest.exp, we get:
...
(xgdb) PASS: gdb.gdb/selftest.exp: send SIGINT signal to child process
^M
Thread 1 "xgdb" received signal SIGINT, Interrupt.^M
0x00007ffff5bf01db in poll () from /lib64/libc.so.6^M
(gdb) FAIL: gdb.gdb/selftest.exp: send ^C to child process again
...
The failure is due to gdb printing 'Thread 1 "xgdb" received signal SIGINT',
but the regexp in the test-case expecting 'Program received signal SIGINT'.
Fix this by updating the regexp, similar to how that is done earlier in the
test-case.
gdb/testsuite/ChangeLog:
2019-08-13 Tom de Vries <tdevries@suse.de>
* gdb.gdb/selftest.exp (send ^C to child process again): Accept also
Thread.