refactor: remove guarded helper headers

tests/popup_test.c

@@ -1,5 +1,4 @@
 #include "test.h"
-#include "../popup_layout.h"
 
 void
 popup_layout(struct ct *t)

tests/wayland_test.c

@@ -1,5 +1,4 @@
 #include "test.h"
-#include "../wayland_state.h"
 
 void
 wayland_press_release_state(struct ct *t)

tests/xim_test.c

@@ -5,8 +5,10 @@
 #include <string.h>
 #include <xcb-imdkit/encoding.h>
 #include <xkbcommon/xkbcommon-keysyms.h>
-#include "../xim/keymap.h"
-#include "../xim/ximtext.h"
+
+uint32_t keymaplookup(const uint32_t*, int, uint16_t);
+char *ximcompound(const char*, size_t, size_t*);
+char *ximutf8compound(const char*, size_t, size_t*);
 
 enum
 {