Delete the old html_json docs stuff.

tools/html_json_doc/test/test_output/test_html_input2.dart

-/**
- * This is a library level dartdoc comment.
- * This should be ignored.
- */
-library testInput2;
-
-/**
- * This is a multi-line dartdoc comment.
- * This is one line.
- * And it keeps going to this line, too.
- */
-/// @docsEditable
-class InputTestCase1 {
-
-}
-
-/// This is a single line dartdoc comment.
-/// @docsEditable
-class InputTestCase2 extends InputTestCase1 {
-
-}
-
-/// This is a multi-line dartdoc comment.
-/// It happens to use multiple single line dartdoc comments.
-/// @docsEditable
-class InputTestCase3 extends InputTestCase2 {
-
-}
-
-/*
- * This is not a dartdoc comment and should not be picked up.
- * The output of this comment should be nothing.
- */
-/// @docsEditable
-class InputTestCase4 {
-
-}
-
-/**
- * This multi-line dartdoc comment doesn't have the /// @docsEditable stuff.
- * This comment should not show up in the JSON.
- * Note that the /// @docsEditable in this line and the one above are ignored.
- */
-class InputTestCase5 {
-
-}
-
-/// This is a single line dartdoc comment that is ignored.
-class InputTestCase6 {
-
-}
-
-/// This is a multi-line dartdoc comment that is ignored.
-/// It is made of multiple single line dartdoc comments.
-class InputTestCase7 {
-
-  /**
-   * This is a multi-line comment on a member.
-   */
-  /// @docsEditable
-  var InputTestCase8;
-
-  /// This is a single line dartdoc comment on a member.
-  /// @docsEditable
-  var InputTestCase9;
-
-  /// This is a multi-line dartdoc comment on a member.
-  /// It is split over two lines.
-  /// @docsEditable
-  var InputTestCase10;
-
-  /**
-   * This multi-line comment on a member is ignored.
-   */
-  var InputTestCase11;
-
-  /// This single line dartdoc comment on a member is ignored.
-  var InputTestCase12;
-}