[expect] optimize compare nodes (#8368)

* [expect] optimize compare nodes 🎨

* Remove needless varible

* Update CHANGELOG.md

Author: Connormiha

CHANGELOG.md

@@ -30,6 +30,7 @@
 - `[docs]` Mention Jest MongoDB Preset ([#8318](https://github.com/facebook/jest/pull/8318))
 - `[@jest/reporters]` Migrate away from `istanbul-api` ([#8294](https://github.com/facebook/jest/pull/8294))
 - `[*]` Delete obsolete emails tag from header comment in test files ([#8377](https://github.com/facebook/jest/pull/8377))
+- `[expect]` optimize compare nodes ([#8368](https://github.com/facebook/jest/pull/8368))
 
 ### Performance
 

packages/expect/src/jasmineUtils.ts

@@ -126,10 +126,8 @@ function eq(
     return false;
   }
 
-  var aIsDomNode = isDomNode(a);
-  var bIsDomNode = isDomNode(b);
   // Use DOM3 method isEqualNode (IE>=9)
-  if (aIsDomNode && typeof a.isEqualNode === 'function' && bIsDomNode) {
+  if (isDomNode(a) && isDomNode(b)) {
     return a.isEqualNode(b);
   }