perf(module:tabs): need add .ant-tabs-tab class reduce css computing time consuming(#7935) (#7936)

Author: doxingg

Diff for: components/tabs/style/patch.less

@@ -4,7 +4,7 @@
   position: relative;
 }
 
-a[nz-tab-link] {
+.ant-tabs-tab a[nz-tab-link] {
   &::before {
     position: absolute;
     top: 0;