Yes, there is a workaround. Remove data-toggle="tooltip"from your markup. This is what causes the tooltip to pop up. Since you still have the data attribute in the tooltip that bootstrap is listening on. Your js constructor is enough, so you don't need to use the data-*tooltip constructor and tooltip constructor in JS.
<input id="testBtn" class="btn btn-default" type="button" value="Test" title="Test Destroy Event"/>
Demo
Update
this is a bug in the old version of Bootstrap, so to fix it in an older version, you can remove the $ tip element by grabbing it from Data.
var $this = $(this);
$this.data('bs.tooltip').$tip.remove();
$this.tooltip('destroy');
Demo
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