feat(module:affix anchor backtop): refactor affix anchor backtop (#1025)

* feat(module:affix anchor back-top): refactor affix anchor back-top

* fix lint

* add test & fix lint & Use NzUpdateHostClassService Instead of class operation

* fix tslint & add edge testing

* add edge testing

* fix tslint

* add tests

PROGRESS.md

@@ -40,13 +40,13 @@
 | datepicker | x | x | x | trotyl | - |
 | timepicker | x | x | x | trotyl | - |
 | calendar | √ | 100% | 100% | trotyl | √ |
-| affix | x | x | x | cipchk | - |
+| affix | √ | 100% | 100% | cipchk | √ |
 | transfer | √ | 100% | 100% | cipchk | x |
 | avatar | √ | 100% | 100% | cipchk | x |
 | list | √ | 100% | 100% | cipchk | x |
 | upload | √ | 100% | 100% | cipchk | x |
-| anchor | x | x | x | cipchk | - |
-| backtop | x | x | x | cipchk | - |
+| anchor | √ | 100% | 100% | cipchk | √ |
+| backtop | √ | 100% | 100% | cipchk | x |
 | divider | √ | 100% | 100% | cipchk | x |
 | treeselect | x | x | x | simplejason | - |
 | tree | x | x | x | simplejason | - |