test: recreate compiler before each test (#3314)

Author: ylemkimon

test/server/Server.test.js

@@ -165,7 +165,7 @@ describe('Server', () => {
     let compiler;
     let server;
 
-    beforeAll(() => {
+    beforeEach(() => {
       compiler = webpack(config);
     });
 

test/server/utils/createDomain.test.js

@@ -10,7 +10,7 @@ describe('createDomain', () => {
   let compiler;
   let server;
 
-  beforeAll(() => {
+  beforeEach(() => {
     compiler = webpack(config);
   });