vm: don't abort process when stack space runs out

Make less assumptions about what objects will be available when
vm context creation or error message printing fail because V8
runs out of JS stack space.

Ref: https://github.com/nodejs/node/issues/6899
PR-URL: https://github.com/nodejs/node/pull/6907


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>