Add dex splitter support.

This is a very minimal first version. This adds support for running the tool on existing
dex code, supplying a mapping file that tells where the individual classes go.
This includes a simple parser for the mapping file, and a simply command line tool to run this.

Missing pieces:
  Proguard map support
  Mapping generation from jar inputs
  Optimized lookup

Change-Id: I7118dae25e8ce53be49ad1ebe70fbdd8fa7c0aa8
diff --git a/src/test/examples/dexsplitsample/Class3.java b/src/test/examples/dexsplitsample/Class3.java
new file mode 100644
index 0000000..98469a5
--- /dev/null
+++ b/src/test/examples/dexsplitsample/Class3.java
@@ -0,0 +1,24 @@
+// Copyright (c) 2018, the R8 project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package dexsplitsample;
+
+public class Class3 extends Class1 {
+  public static void main(String[] args) {
+    Class3 clazz = new Class3();
+    if (clazz.getClass1String() != "Class1String") {
+      throw new RuntimeException("Can't call method from super");
+    }
+    if (!new InnerClass().success()) {
+      throw new RuntimeException("Can't call method on inner class");
+    }
+    System.out.println("Class3");
+  }
+
+  private static class InnerClass {
+    public boolean success() {
+      return true;
+    }
+  }
+}