V8 inspector shutdown crash

[CedricGuillemet]

C++ Check added with this PR : BabylonJS/BabylonNative#1277
to shutdown and restart. At 1st shutdown, there is a crash due to V8 inspector not being properly stopped.

[bghgary]

Maybe related: #21

[CedricGuillemet]

#21

Yes, it looks like the same one

[thomlucc]

fixed