kde/kwin: Disable building tests as well (!243)

We specify !check option to not run kwin tests, might as well disable
building them, as they take about 50% of compile time.

[ci:skip-build]

kde/kwin/APKBUILD

@@ -22,7 +22,8 @@ build() {
 	cmake \
 		-DCMAKE_BUILD_TYPE=Release \
 		-DCMAKE_INSTALL_PREFIX=/usr \
-		-DCMAKE_INSTALL_LIBDIR=lib
+		-DCMAKE_INSTALL_LIBDIR=lib \
+		-DBUILD_TESTING=false
 	make
 }