fix(ui): (dev) task: reset NODE_ENV

Author: Guillaume Chau

packages/@vue/cli-ui/src/graphql-api/connectors/tasks.js

@@ -292,11 +292,18 @@ async function run (id, context) {
 
     process.env.VUE_CLI_CONTEXT = cwd.get()
 
+    const nodeEnv = process.env.NODE_ENV
+    delete process.env.NODE_ENV
+
     const child = execa(command, args, {
       cwd: cwd.get(),
       stdio: ['inherit', 'pipe', 'pipe']
     })
 
+    if (typeof nodeEnv !== 'undefined') {
+      process.env.NODE_ENV = nodeEnv
+    }
+
     task.child = child
 
     const outPipe = logPipe(queue => {