remove useless if-before-free tests

remove useless if-before-free tests

* lib-src/ebrowse.c (xfree): Likewise.
* lib-src/etags.c (process_file_name, free_tree, free_fdesc): Likewise.
(popclass_above, Prolog_functions, Erlang_functions): Likewise.
* lib-src/pop.c (pop_quit): Likewise.
* lwlib/lwlib-Xm.c (xm_update_one_value): Likewise.
* lwlib/lwlib.c (safe_free_str, free_widget_value_tree): Likewise.
* src/editfns.c (Fset_time_zone_rule): Likewise.
* src/lread.c (nosuffix): Likewise.
* src/ralloc.c (get_bloc): Likewise.
* src/regex.c (reg_free): Likewise.
* src/xftfont.c (xftfont_open, xftfont_close): Likewise.
* src/xrdb.c (get_user_app, get_environ_db, x_load_resources): Likewise.
* src/xsmfns.c (smc_save_yourself_CB): Likewise.