Commented Issue: [BUG] Hang on application pool recycle [119]

Hi,

Using React.NET 3.0.1 which uses ClearScript.V8 5.4.8 following hang is observed on recycling application pool
```
.NET Call Stack


.SharedPtr.Release(SharedPtr*)+d7
[[InlinedCallFrame] (.Decrement)] .RefCount.Decrement(RefCount*)
Microsoft.ClearScript.V8.V8ContextProxyImpl.!V8ContextProxyImpl()+4e
Microsoft.ClearScript.V8.V8ContextProxyImpl.Dispose(Boolean)+1f
[[DebuggerU2MCatchHandlerFrame]]
[[ContextTransitionFrame]]
[[GCFrame]]
[[DebuggerU2MCatchHandlerFrame]]

Full Call Stack

ntdll!NtWaitForSingleObject+14
KERNELBASE!WaitForSingleObjectEx+8f
v8_x64!v8::Extension::dependencies+329ac
v8_x64!v8::ExternalResourceVisitor::VisitExternalString+28187
v8_x64!v8::ExternalResourceVisitor::VisitExternalString+1a3
v8_x64!v8::ExternalResourceVisitor::VisitExternalString+533b
ClearScriptV8_64+14216
ClearScriptV8_64+120e4
ClearScriptV8_64+13e3f
ClearScriptV8_64+50a8
<Module>.SharedPtr<V8Context>.Release(SharedPtr<V8Context>*)+d7
[[InlinedCallFrame] (<Module>.Decrement)] <Module>.RefCount.Decrement(RefCount*)
Microsoft.ClearScript.V8.V8ContextProxyImpl.!V8ContextProxyImpl()+4e
Microsoft.ClearScript.V8.V8ContextProxyImpl.Dispose(Boolean)+1f
clr!FastCallFinalizeWorker+6
clr!ETW::GCLog::SendFinalizeObjectEvent+c9
clr!MethodTable::CallFinalizer+b5
clr!CallFinalizer+5e
clr!FinalizerThread::DoOneFinalization+95
clr!FinalizerThread::FinalizeAllObjects+133
clr!FinalizerThread::FinalizeAllObjects_Wrapper+18
clr!Frame::Push+59
clr!PEDecoder::GetNativeCodeManagerTable+170
clr!PEDecoder::GetNativeCodeManagerTable+99
[[DebuggerU2MCatchHandlerFrame]]
clr!Thread::ShouldChangeAbortToUnload+45
clr!Thread::DoADCallBack+109
[[ContextTransitionFrame]]
clr!Frame::Push+a2
clr!FinalizerThread::DoOneFinalization+1f9
[[GCFrame]]
clr!FinalizerThread::FinalizeAllObjects+133
clr!FinalizerThread::FinalizerThreadWorker+bb
clr!Frame::Push+59
clr!PEDecoder::GetNativeCodeManagerTable+170
clr!PEDecoder::GetNativeCodeManagerTable+99
[[DebuggerU2MCatchHandlerFrame]]
clr!FinalizerThread::FinalizerThreadStart+10a
clr!Thread::intermediateThreadProc+86
kernel32!BaseThreadInitThunk+14
ntdll!RtlUserThreadStart+21
```
Comments: We've posted a potential fix [here](https://clearscript.codeplex.com/SourceControl/changeset/1db6dbc9d458ec5fafa15d5574a0e2709a1b220d). Since we haven't been able to reproduce the issue, it would be great if you could give it a try. As the fix is relative to ClearScript 5.4.9, you might pick up some performance improvements as well. Good luck, and thanks again!