Make test names unique in python.exp and guile.exp

Make test names unique in python.exp and guile.exp

Version 2, handles the comments of Simon and Pedro.

Note that gdb_test_multiline and gdb_py_test_multiple are using
the "input line" as the test name, and so when there is a duplicated
input line (such as a line containing "end"), we have duplicated test
names => as gdb_test_multiline and gdb_py_test_multiple are identical,
as indicated in FIXME, move this to gdb.exp, and make the test name unique
by adding the inputnr to the pass message for each input.

2020-06-26  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* lib/gdb.exp (gdb_test_multiline): New, moved from gdb-guile.exp,
	have a input seq nr in each pass message.
        * lib/gdb-guile.exp (gdb_test_multiline): Move to gdb.exp.
	* lib/gdb-python.exp (gdb_py_test_multiple): Remove.
	* gdb.python/python.exp: Make test names unique,
	use gdb_test_multiline instead of gdb_py_test_multiple,
	use $gdb_test_name.
	* gdb.guile/guile.exp: Make test names unique, use $gdb_test_name