pkg/docgen: putting test code in file system

pkg/docgen/test/multi_library_code/lib/temp2.dart

+library testLib2.foo;
+import 'temp.dart';
+
+/**
+ * Doc comment for class [B].
+ *
+ * Multiline Test
+ */
+
+/*
+ * Normal comment for class B.
+ */
+class B extends A {
+
+  B();
+  B.fooBar();
+
+  /**
+   * Test for linking to super
+   */
+  int doElse(int b) {
+    print(b);
+    return b;
+  }
+
+  /**
+   * Test for linking to parameter [c]
+   */
+  void doThis(int c) {
+    print(c);
+  }
+}
+
+int testFunc(int a) {
+  return a;
+}