gdb/testsuite: resolve duplicate test names in gdb.guile/scm-breakpoint.exp

Extend some test names to avoid duplicates.

gdb/testsuite/ChangeLog:

	* gdb.guile/scm-breakpoint.exp (test_bkpt_basic): Extend test
	names to avoid duplicates.
	(test_bkpt_cond_and_cmds): Likewise.
	(test_bkpt_eval_funcs): Likewise.