Move test and add return type

There's a weird interaction with typechecks that means we need an explicit return type here.

Author: odersky

tests/run-macros/i11630.scala renamed to tests/run/i11630.scala

@@ -1,9 +1,9 @@
 inline def failme1() = compiletime.error("fail")
 transparent inline def failme2() = compiletime.error("fail")
 
-@main def Test =
+@main def Test: Unit = {
   assert(!compiletime.testing.typeChecks("failme1()"))
   assert(!compiletime.testing.typeChecks("failme2()"))
   assert(!compiletime.testing.typeChecks("a b c"))
   assert(!compiletime.testing.typeChecks("true: Int"))
-
+}