sometimes, instance are kept alive by stack. give it a bit more timeout and clear object in other method.

while looking around this code path, I realized we are putting p2p references to implicit cache.

this is bad since p2p graph is already implicitly cached by root compilation and the implicit cache is for things like winform which uses Roslyn without explicit cache from us.

this p2p causes compilation for winform to be kicked out from implicit cache for no reason.