Generate a callsite identifier associated with each callsite

1. Generate a unique string name for a callsite that appears in every node
2. This identifier will refer to a single callsite and is used for trace data retrieval

@ke-yu
@lukechurch
@Steell
@Benglin

The intention is to increment what is cached in the dictionary.
So whenever theres a new function call within the same GUID, the count is always incremented.