gdb/testsuite: make test names unique in gdb.python/py-finish-breakpoint.exp

gdb/testsuite: make test names unique in gdb.python/py-finish-breakpoint.exp

Make test names unique by just adding additional text to the test
names.  As this is a Python test that repeatedly imports the Python
script I've just numbered the test names in this case rather than
trying to come up with anything better, hence we have:

  import python scripts, 1
  import python scripts, 2
  ...
  import python scripts, 6

Not great, but hopefully good enough.  Everything else has a slightly
more descriptive test name.

gdb/testsuite/ChangeLog:

	* gdb.python/py-finish-breakpoint.exp: Make test names unique.