title: <ng-template></ng-template> is loading multiple times
body: <p>I am using ngTemplateOutlet to load . but It loads a template multiple times .It is loading correct template but it executing multiple times loadTemplate() method.</p>
  
  <p>In <strong>HTML</strong>:</p>
  
  <pre><code>&lt;table&gt;
      &lt;thead&gt;
      &lt;/thead&gt;
      &lt;tbody&gt;
          &lt;ng-template [ngTemplateOutlet]="loadTemplate()"&gt;&lt;/ng-template&gt;
      &lt;/tbody&gt;
  &lt;/table&gt;
  
  &lt;ng-template #template1&gt;
      &lt;tr *ngFor="iteration"&gt;
          &lt;p&gt;Hiii&lt;/p&gt;
      &lt;/tr&gt;
  &lt;/ng-template&gt;
  
  &lt;ng-template #template2&gt;
      &lt;tr *ngFor="iteration"&gt;
          &lt;p&gt;Byee&lt;/p&gt;
      &lt;/tr&gt;
  &lt;/ng-template&gt;
  </code></pre>
  
  <p>In my <strong>component.ts</strong>:</p>
  
  <pre><code>@ViewChild('template1') template1: TemplateRef&lt;any&gt;;
  @ViewChild('template1') template1: TemplateRef&lt;any&gt;;
  loadTemplate(){
      if (condition)
          return this.template1;
  
      return this.template2;
  }
  </code></pre>