wl: modmask's caller has already looked at the keymap

grabkey returns before it asks for the mask when there is no keyboard
state, so the guard inside modmask answered a question nobody put to it --
except the test, which was the only caller that could reach it.  A check
kept alive by the test that reaches it is one line of code and one line of
test to delete.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/wl_adapter_test.c

@@ -40,8 +40,6 @@ wl_modifier_mask(struct ct *t)
 	struct xkb_keymap *km;
 	xkb_mod_mask_t caps, ctrl, shift;
 
-	kstate = nil;
-	CT_EQ_UINT(t, 0, modmask());	/* before any keymap arrives */
 	ctx = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
 	km = xkb_keymap_new_from_string(ctx, keymaptext,
 		XKB_KEYMAP_FORMAT_TEXT_V1, XKB_KEYMAP_COMPILE_NO_FLAGS);