[code] Fix the env $PATH when the go lsp spawned in windows (#45011)

The env name 'PATH' is not applied on windows system.

x-pack/legacy/plugins/code/server/lsp/go_launcher.ts

@@ -87,15 +87,13 @@ export class GoServerLauncher extends AbstractLauncher {
       throw new Error('Cannot find executable go language server');
     }
 
-    let envPath = process.env.PATH;
     const goToolchain = await this.getBundledGoToolchain(installationPath, log);
     if (!goToolchain) {
       throw new Error('Cannot find go toolchain in bundle installation');
     }
     // Construct $GOROOT from the bundled go toolchain.
     const goRoot = goToolchain;
     const goHome = path.resolve(goToolchain, 'bin');
-    envPath = process.platform === 'win32' ? envPath + ';' + goHome : envPath + ':' + goHome;
     // Construct $GOPATH under 'kibana/data/code'.
     const goPath = this.options.goPath;
     if (!fs.existsSync(goPath)) {
@@ -104,17 +102,18 @@ export class GoServerLauncher extends AbstractLauncher {
     const goCache = path.resolve(goPath, '.cache');
     const params: string[] = ['-port=' + port.toString()];
     const golsp = path.resolve(installationPath, launchersFound[0]);
+    const env = Object.create(process.env);
+    env.PATH = process.platform === 'win32' ? goHome + ';' + env.PATH : goHome + ':' + env.PATH;
     const p = spawn(golsp, params, {
       detached: false,
       stdio: 'pipe',
       env: {
-        ...process.env,
+        ...env,
         CLIENT_HOST: '127.0.0.1',
         CLIENT_PORT: port.toString(),
         GOROOT: goRoot,
         GOPATH: goPath,
         GOCACHE: goCache,
-        PATH: envPath,
         CGO_ENABLED: '0',
       },
     });