add test

/

Change-Id: Iee56fe799ceda0a9f650378537c3c195242788c6

Author: qiulaidongfeng

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

@@ -0,0 +1,18 @@
+# Test query for non-defaults in the env 
+
+env GOTOOLCHAIN=local
+env GOSUMDB=nodefault
+env GOPROXY=nodefault
+env GO111MODULE=auto
+
+go env -changed
+stdout 'GOTOOLCHAIN=local'
+stdout 'GOSUMDB=nodefault'
+stdout 'GOPROXY=nodefault'
+stdout 'GO111MODULE=auto'
+
+go env -changed -json
+stdout '"GOTOOLCHAIN": "local"'
+stdout '"GOSUMDB": "nodefault"'
+stdout '"GOPROXY": "nodefault"'
+stdout '"GO111MODULE": "auto"'