move tests to Dotty format

tests/run/StringConcat.scala

@@ -0,0 +1,79 @@
+@main def Test() = {
+
+  // This should generally obey 15.18.1. of the JLS (String Concatenation Operator +)
+  def concatenatingVariousTypes(): String = {
+    val str: String = "some string"
+    val sb: StringBuffer = new StringBuffer("some stringbuffer")
+    val cs: CharSequence = java.nio.CharBuffer.allocate(50).append("charsequence")
+    val i: Int = 123456789
+    val s: Short = 345
+    val b: Byte = 12
+    val z: Boolean = true
+    val f: Float = 3.14f
+    val j: Long = 98762147483647L
+    val d: Double = 3.1415d
+
+    "String " + str + "\n" +
+      "StringBuffer " + sb + "\n" +
+      "CharSequence " + cs + "\n" +
+      "Int " + i + "\n" +
+      "Short " + s + "\n" +
+      "Byte " + b + "\n" +
+      "Boolean " + z + "\n" +
+      "Float " + f + "\n" +
+      "Long " + j + "\n" +
+      "Double " + d + "\n"
+  }
+  // The characters `\u0001` and `\u0002` play a special role in `StringConcatFactory`
+  def concatenationInvolvingSpecialCharacters(): String = {
+    val s1 = "Qux"
+    val s2 = "Quux"
+
+    s"Foo \u0001 $s1 Bar \u0002 $s2 Baz"
+  }
+  // Concatenation involving more than 200 elements
+  def largeConcatenation(): String = {
+    val s00 = "s00"
+    val s01 = "s01"
+    val s02 = "s02"
+    val s03 = "s03"
+    val s04 = "s04"
+    val s05 = "s05"
+    val s06 = "s06"
+    val s07 = "s07"
+    val s08 = "s08"
+
+    // 24 rows follow
+    ((s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n") +
+      (s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n")) +
+      ((s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n") +
+      (s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n" +
+      s00 + "," + s01 + "," + s02 + "," + s03 + "," + s04 + "," + s05 + "," + s06 + "," + s07 + "," + s08 + "\n"))
+  }
+  println("----------")
+  println(concatenatingVariousTypes())
+  println("----------")
+  println(concatenationInvolvingSpecialCharacters())
+  println("----------")
+  println(largeConcatenation())
+  println("----------")
+}