Fixed v8-heap memory leak, when using API-functions with run(async)-call.
Fixed v8-heap memory leak, when using API-functions with run(async)-call.

ndob/duktape-node,ndob/duktape-node,yosuke-furukawa/duktape-node,Oceanswave/duktape-node,yosuke-furukawa/duktape-node,Oceanswave/duktape-node,ndob/duktape-node,yosuke-furukawa/duktape-node,Oceanswave/duktape-node