Fix import problem in dart generated files. (fixes #7609). (#7621)

* Fix import problem in dart generated files. (fixes #7609).

* Fix naming.

* Fix minor changes in generated files.

* Add some tests. Fix minor problems.

* Fix minor format problem plus import alias issue.

* Minor fix in dart code generator, remove java from examples

* remove java and go generated files

* Fix dart tests.

* Fix spell problem.

* Remove excessive tests :))

Co-authored-by: Derek Bailey <derekbailey@google.com>

tests/include_test1_generated.dart

@@ -0,0 +1,109 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+// ignore_for_file: unused_import, unused_field, unused_element, unused_local_variable
+
+import 'dart:typed_data' show Uint8List;
+import 'package:flat_buffers/flat_buffers.dart' as fb;
+
+
+import './include_test2_my_game.other_name_space_generated.dart' as my_game_other_name_space;
+
+class TableA {
+  TableA._(this._bc, this._bcOffset);
+  factory TableA(List<int> bytes) {
+    final rootRef = fb.BufferContext.fromBytes(bytes);
+    return reader.read(rootRef, 0);
+  }
+
+  static const fb.Reader<TableA> reader = _TableAReader();
+
+  final fb.BufferContext _bc;
+  final int _bcOffset;
+
+  my_game_other_name_space.TableB? get b => my_game_other_name_space.TableB.reader.vTableGetNullable(_bc, _bcOffset, 4);
+
+  @override
+  String toString() {
+    return 'TableA{b: ${b}}';
+  }
+
+  TableAT unpack() => TableAT(
+      b: b?.unpack());
+
+  static int pack(fb.Builder fbBuilder, TableAT? object) {
+    if (object == null) return 0;
+    return object.pack(fbBuilder);
+  }
+}
+
+class TableAT implements fb.Packable {
+  my_game_other_name_space.TableBT? b;
+
+  TableAT({
+      this.b});
+
+  @override
+  int pack(fb.Builder fbBuilder) {
+    final int? bOffset = b?.pack(fbBuilder);
+    fbBuilder.startTable(1);
+    fbBuilder.addOffset(0, bOffset);
+    return fbBuilder.endTable();
+  }
+
+  @override
+  String toString() {
+    return 'TableAT{b: ${b}}';
+  }
+}
+
+class _TableAReader extends fb.TableReader<TableA> {
+  const _TableAReader();
+
+  @override
+  TableA createObject(fb.BufferContext bc, int offset) => 
+    TableA._(bc, offset);
+}
+
+class TableABuilder {
+  TableABuilder(this.fbBuilder);
+
+  final fb.Builder fbBuilder;
+
+  void begin() {
+    fbBuilder.startTable(1);
+  }
+
+  int addBOffset(int? offset) {
+    fbBuilder.addOffset(0, offset);
+    return fbBuilder.offset;
+  }
+
+  int finish() {
+    return fbBuilder.endTable();
+  }
+}
+
+class TableAObjectBuilder extends fb.ObjectBuilder {
+  final my_game_other_name_space.TableBObjectBuilder? _b;
+
+  TableAObjectBuilder({
+    my_game_other_name_space.TableBObjectBuilder? b,
+  })
+      : _b = b;
+
+  /// Finish building, and store into the [fbBuilder].
+  @override
+  int finish(fb.Builder fbBuilder) {
+    final int? bOffset = _b?.getOrCreateOffset(fbBuilder);
+    fbBuilder.startTable(1);
+    fbBuilder.addOffset(0, bOffset);
+    return fbBuilder.endTable();
+  }
+
+  /// Convenience method to serialize to byte list.
+  @override
+  Uint8List toBytes([String? fileIdentifier]) {
+    final fbBuilder = fb.Builder(deduplicateTables: false);
+    fbBuilder.finish(finish(fbBuilder), fileIdentifier);
+    return fbBuilder.buffer;
+  }
+}