os2: cleanup

core/os/os2/env_windows.odin

@@ -8,6 +8,7 @@ _lookup_env :: proc(key: string, allocator: runtime.Allocator) -> (value: string
 	if key == "" {
 		return
 	}
+	assert(!is_temp(allocator))
 	TEMP_ALLOCATOR_GUARD()
 	wkey, _ := win32_utf8_to_wstring(key, temp_allocator())
 
@@ -20,8 +21,6 @@ _lookup_env :: proc(key: string, allocator: runtime.Allocator) -> (value: string
 		return "", true
 	}
 
-	TEMP_ALLOCATOR_GUARD()
-
 	b := make([]u16, n+1, temp_allocator())
 
 	n = win32.GetEnvironmentVariableW(wkey, raw_data(b), u32(len(b)))