[故障]解决了select组件要支持点击下拉按钮回收下拉框的问题，解决了@3651，关联RDC:AIMatrix-149184

Change-Id: I4d3a757bd6c1d2022132ddd6c0107fa983220396

Author: 张淑婷00344668

src/jigsaw/pc-components/combo-select/combo-select.html

@@ -32,6 +32,7 @@
     <i class="iconfont iconfont-e14b jigsaw-combo-select-clear" [ngStyle]="{right: this.selectIcon ? '20px' : '7px'}"
        *ngIf="clearable && value && value.length != 0" (click)="_$clearValue($event)">
     </i>
-    <i class="jigsaw-combo-select-arrow jigsaw-combo-select-down" [ngClass]="selectArrowClass"></i>
+    <i class="jigsaw-combo-select-arrow jigsaw-combo-select-down" [ngClass]="selectArrowClass"
+       (click)="_$handleArrowClick($event)"></i>
 </div>
 <ng-content></ng-content>

src/jigsaw/pc-components/combo-select/combo-select.ts

@@ -458,6 +458,28 @@ export class JigsawComboSelect extends AbstractJigsawComponent implements Contro
         this.searchKeywordChange.emit(this.searchKeyword);
     }
 
+    /* Started by AICoder, pid:i5aa7hffb2947e6144b60964401d5e102379feae */
+    /**
+     * @internal
+     * 处理箭头点击事件，可以被子类覆盖
+     */
+    public _$handleArrowClick(event: Event): void {
+        event.preventDefault();
+        event.stopPropagation();
+
+        // 如果是禁用状态，不处理点击事件
+        if (this.disabled) {
+            return;
+        }
+
+        // 如果当前是打开状态，则关闭
+        this.open = !this._$opened;
+
+        // 触发touched回调
+        this._onTouched();
+    }
+    /* Ended by AICoder, pid:i5aa7hffb2947e6144b60964401d5e102379feae */
+
     public ngOnInit() {
         super.ngOnInit();
         // 设置初始值