Add regression test

Author: nicolasstucki

tests/pos-macros/null-by-name/Macro_1.scala

@@ -0,0 +1,10 @@
+import scala.quoted.*
+
+inline def foo(x: => Any): Unit =
+  ${ impl('x) }
+
+private def impl(x: Expr[Any])(using Quotes) : Expr[Unit] = {
+  '{
+    val a = $x
+  }
+}

tests/pos-macros/null-by-name/Test_2.scala

@@ -0,0 +1 @@
+def test = foo(null)