Don't leak env variables from batch files

scripts/code.bat

 @echo off
+setlocal
+
 title VSCode Dev
 
 pushd %~dp0\..
@@ -23,9 +25,4 @@ set ELECTRON_ENABLE_STACK_DUMPING=1
 .\.build\electron\electron.exe . %*
 popd
 
-:: Unset environment variables after we are done
-set NODE_ENV=
-set VSCODE_DEV=
-set ELECTRON_DEFAULT_ERROR_MODE=
-set ELECTRON_ENABLE_LOGGING=
-set ELECTRON_ENABLE_STACK_DUMPING=
\ No newline at end of file
+endlocal
\ No newline at end of file

scripts/test.bat

 @echo off
+setlocal
 
 set ATOM_SHELL_INTERNAL_RUN_AS_NODE=1
 
 pushd %~dp0\..
 .\.build\electron\electron.exe .\node_modules\mocha\bin\_mocha %*
 popd
+
+endlocal
\ No newline at end of file