gdb/testsuite: resolve remaining duplicate test names in gdb.python/*.exp

This commit resolves the remaining duplicate test names in the
gdb.python/ directory, there's 1 duplicate per test script.  In each
case I have just extended some test names to make them more
descriptive.

gdb/testsuite/ChangeLog:

	* gdb.python/py-bad-printers.exp: Extend test names to make them
	unique.
	* gdb.python/py-events.exp: Likewise.
	* gdb.python/py-finish-breakpoint2.exp: Likewise.
	* gdb.python/py-frame-inline.exp: Likewise.
	* gdb.python/py-frame.exp: Likewise.
	* gdb.python/py-infthread.exp: Likewise.