test: check range fix for slowToString
test: check range fix for slowToString

Verify that start and end are coerced properly.

Ref: https://github.com/nodejs/node/pull/2919
PR-URL: https://github.com/nodejs/node/pull/4019
Reviewed-By: Trevor Norris <9cb5491eb5770dd8e0bf77a8a0335abf5f0488c5@gmail.com>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node