util,assert: fix boxed primitives bug

Currently the comparison could throw an error in case a boxed
primitive has no valueOf function on one side of the assert call.

PR-URL: #22243
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: George Adams <george.adams@uk.ibm.com>

lib/internal/util/comparisons.js

@@ -120,6 +120,9 @@ function strictDeepEqual(val1, val2, memos) {
     const val1Value = val1.valueOf();
     // Note: Boxed string keys are going to be compared again by Object.keys
     if (val1Value !== val1) {
+      if (typeof val2.valueOf !== 'function') {
+        return false;
+      }
       if (!innerDeepEqual(val1Value, val2.valueOf(), true))
         return false;
       // Fast path for boxed primitives

test/parallel/test-assert-deep.js

@@ -931,3 +931,10 @@ assert.throws(() => assert.deepStrictEqual(new Boolean(true), {}),
   );
   util.inspect.defaultOptions = tmp;
 }
+
+// Basic valueOf check.
+{
+  const a = new String(1);
+  a.valueOf = undefined;
+  assertNotDeepOrStrict(a, new String(1));
+}