treewide: parallel tests

Most tests already had no global state, however parallel was never enabled. This change enables it for all applicable tests.

Signed-off-by: Ophestra <cat@gensokyo.uk>

system/dbus/proc_test.go

@@ -8,8 +8,4 @@ import (
 	"hakurei.app/helper"
 )
 
-func TestMain(m *testing.M) {
-	container.TryArgv0(nil)
-	helper.InternalHelperStub()
-	os.Exit(m.Run())
-}
+func TestMain(m *testing.M) { container.TryArgv0(nil); helper.InternalHelperStub(); os.Exit(m.Run()) }