fix(codegen): add explicit any to class fields

fixes angular#8204

Closes angular#8205

Author: alexeagle

modules/angular2/src/compiler/output/ts_emitter.ts

@@ -130,6 +130,8 @@ class _TsEmitterVisitor extends AbstractEmitterVisitor implements o.TypeVisitor
     if (isPresent(field.type)) {
       ctx.print(`:`);
       field.type.visitType(this, ctx);
+    } else {
+      ctx.print(`: any`);
     }
     ctx.println(`;`);
   }

modules/angular2/test/compiler/output/ts_emitter_spec.ts

@@ -235,7 +235,7 @@ export function main() {
       it('should support declaring fields', () => {
         expect(emitStmt(new o.ClassStmt('SomeClass', null, [new o.ClassField('someField')], [],
                                         null, [])))
-            .toEqual(['class SomeClass {', '  someField;', '}'].join('\n'));
+            .toEqual(['class SomeClass {', '  someField: any;', '}'].join('\n'));
         expect(emitStmt(new o.ClassStmt('SomeClass', null,
                                         [new o.ClassField('someField', o.INT_TYPE)], [], null, [])))
             .toEqual(['class SomeClass {', '  someField:number;', '}'].join('\n'));