gdb/23712: Cleanup/Remove temporary dictionary functions

Now that multidictionary's are being used, there is no longer any need
to retain the four temporary functions introduced in the beginning of
this series.

This patch removes them.

As an additional cleanup, since the single-language dictionaries are
no longer used outside dictionary.c, make all of those functions
static.

gdb/ChangeLog:

	PR gdb/23712
	PR symtab/23010
	* dictionary.c (pending_to_vector): Remove.
	(dict_create_hashed_1, dict_create_linear_1, dict_add_pending_1):
	Remove _1 suffix, replacing functions of the same name.  Update
	all callers.
	(dict_create_hashed, dict_create_hashed_expandable)
	(dict_create_linear, dict_create_linear_expandable, dict_free)
	(dict_add_symbol, dict_add_pending, dict_size, dict_empty):
	Make functions static.