[gdb/testsuite] Fix gdb.server/no-thread-db.exp with local-remote-host.exp

[gdb/testsuite] Fix gdb.server/no-thread-db.exp with local-remote-host.exp

With test-case gdb.server/no-thread-db.exp and host board local-remote-host.exp
with a tentative fix for PR29697 I run into:
...
(gdb) print foo^M
Cannot find thread-local storage for Thread 29613.29613, executable file \
  $HOME/no-thread-db:^M
Remote target failed to process qGetTLSAddr request^M
(gdb) FAIL: gdb.server/no-thread-db.exp: print foo
...

The regexp in the test-case expects the full $binfile pathname, but we have
instead $HOME/no-thread-db.

Fix this by making the regexp less strict.

Tested on x86_64-linux.