posix: remove the is_temp things that prevented use-after-frees

https://github.com/odin-lang/Odin/commit/d0709a7de21efded4625167dbff4a7dd13d561b4
fixes those another way.

core/os/os2/temp_file_linux.odin

@@ -4,7 +4,7 @@ package os2
 import "base:runtime"
 
 _temp_dir :: proc(allocator: runtime.Allocator) -> (string, runtime.Allocator_Error) {
-	TEMP_ALLOCATOR_GUARD(ignore=is_temp(allocator))
+	TEMP_ALLOCATOR_GUARD()
 	tmpdir := get_env("TMPDIR", temp_allocator())
 	if tmpdir == "" {
 		tmpdir = "/tmp"