fix the script path we use to set the v8 bp
fix the script path we use to set the v8 bp

We were using the original path provided by the Debug API rather than the app
local path we computed based on the file-matching heuristics.

DominicKramer/cloud-debug-nodejs,matthewloring/cloud-debug-nodejs,DominicKramer/cloud-debug-nodejs,ofrobots/cloud-debug-nodejs,matthewloring/cloud-debug-nodejs,googleapis/cloud-debug-nodejs,ofrobots/cloud-debug-nodejs,ofrobots/cloud-debug-nodejs,matthewloring/cloud-debug-nodejs,googleapis/cloud-debug-nodejs,DominicKramer/cloud-debug-nodejs,googleapis/cloud-debug-nodejs