Do not dispatch 'change' events during pressing spin buttons for input[type=number].

Source/core/html/HTMLTextFormControlElement.cpp

Index: Source/core/html/HTMLTextFormControlElement.cpp
diff --git a/Source/core/html/HTMLTextFormControlElement.cpp b/Source/core/html/HTMLTextFormControlElement.cpp
index 0a0c83fd50aa24ac96ba60d9743a11c469c67610..f389dd44b0668d7b1e07e4fdebf5d9ffd2171f5a 100644
--- a/Source/core/html/HTMLTextFormControlElement.cpp
+++ b/Source/core/html/HTMLTextFormControlElement.cpp
@@ -183,7 +183,7 @@ void HTMLTextFormControlElement::select()
 
 void HTMLTextFormControlElement::dispatchFormControlChangeEvent()
 {
-    if (m_textAsOfLastFormControlChangeEvent != value()) {
+    if (!equalIgnoringNullity(m_textAsOfLastFormControlChangeEvent, value())) {
         dispatchChangeEvent();
         setTextAsOfLastFormControlChangeEvent(value());
     }