policy: revise manifest.js to avoid empty blocks

PR-URL: #41831
Refs: https://eslint.org/docs/rules/no-empty
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

lib/internal/policy/manifest.js

@@ -430,12 +430,11 @@ class Manifest {
 
     if (objectButNotArray(obj) && 'onerror' in obj) {
       const behavior = obj.onerror;
-      if (behavior === 'throw') {
-      } else if (behavior === 'exit') {
+      if (behavior === 'exit') {
         reaction = REACTION_EXIT;
       } else if (behavior === 'log') {
         reaction = REACTION_LOG;
-      } else {
+      } else if (behavior !== 'throw') {
         throw new ERR_MANIFEST_UNKNOWN_ONERROR(behavior);
       }
     }
@@ -579,8 +578,7 @@ class Manifest {
         const entry = this.#scopeIntegrities.get(scope);
         if (entry === true) {
           return true;
-        } else if (entry === kCascade) {
-        } else {
+        } else if (entry !== kCascade) {
           break;
         }
       }