Add Playground to make debugging easier in Metals

Author: adpi2

compiler/test/dotty/tools/dotc/Playground.scala

@@ -0,0 +1,13 @@
+package dotty.tools.dotc
+
+import dotty.tools.vulpix._
+import org.junit.Test
+import org.junit.Ignore
+
+@Ignore class Playground:
+  import TestConfiguration._
+  import CompilationTests._
+
+  @Test def example: Unit =
+    implicit val testGroup: TestGroup = TestGroup("playground")
+    compileFile("tests/playground/example.scala", defaultOptions).checkCompile()

tests/playground/example.scala

@@ -0,0 +1,4 @@
+object Test:
+  val foo: Int = 2
+  def bar(x: Int): Int = x + x
+  bar(foo)