Remove localtime_tz and strftime_tz.

This also brings our copy of strftime.c much closer to upstream, though
we still have several GNU extensions and hacks to deal with Android32's
broken time_t.

Bug: 15765976
Change-Id: Ic9ef36e8acd3619504ecc4d73feec2b61fd4dfa1

libc/tzcode/localtime.c

@@ -2310,20 +2310,4 @@ __attribute__((visibility("default"))) time_t mktime_tz(struct tm* const tmp, co
   return return_value;
 }
 
-// Non-standard API: localtime(3) but with an explicit timezone parameter.
-#if !defined(__LP64__)
-__attribute__((visibility("default"))) void localtime_tz(const time_t* const timep, struct tm* tmp, const char* tz) {
-  struct state* st = malloc(sizeof(*st));
-
-  if (st == NULL)
-    return;
-  if (__bionic_tzload_cached(tz, st, TRUE) != 0) {
-    // TODO: not sure what's best here, but for now, we fall back to gmt.
-    gmtload(st);
-  }
-  localsub(timep, 0L, tmp, st);
-  free(st);
-}
-#endif
-
 // END android-added