cmd/go: fix TestScript/work_env

Author: psilva261

src/cmd/go/testdata/script/work_env.txt

@@ -1,7 +1,7 @@
 go env GOWORK
 stdout '^'$GOPATH'[\\/]src[\\/]go.work$'
 go env
-stdout '^(set )?GOWORK="?'$GOPATH'[\\/]src[\\/]go.work"?$'
+stdout '^(set )?GOWORK=["'']?'$GOPATH'[\\/]src[\\/]go.work["'']?$'
 
 cd ..
 go env GOWORK