*: kill bb_get_last_path_component, replace with two functions

(one which strips trailing slash and one which does not)
wget: straighten out as a result of above change
   text    data     bss     dec     hex filename
   5056       1       0    5057    13c1 busybox.t4/networking/wget.o
   5022       0       0    5022    139e busybox.t5/networking/wget.o

coreutils/basename.c

@@ -34,7 +34,8 @@ int basename_main(int argc, char **argv)
 		bb_show_usage();
 	}
 
-	s = bb_get_last_path_component(*++argv);
+	/* It should strip slash: /abc/def/ -> def */
+	s = bb_get_last_path_component_strip(*++argv);
 
 	if (*++argv) {
 		n = strlen(*argv);