Resolution root bound dependency expression de-duplication

[dadhi]

In V3 I have removed Expression level cache stored once per Factory. This simlified a problem with condition based resolution, and removed a whole lot of adhoc checks.

Problem

• This also introduced a problem of possibly multiple equivalent but not the same dependency expressions. In case when expression is or contains a lambda, the lambda will be compiled to different multiple delegates by FEC
• Increased the size of result expession if it contains equivalent sub-expressions.

Solution

Memoize the built dependency expression into resolution root Request by the FactoryId. Exluding wrappers. Use the memoized expression instead of building a new one.
For open-generics we will use id of closed factory.

It is not a cache, cause it will be dropped when result expression is build and compiled.
This is similar to storing expression in a local var and using this var multiple times to build the result.

[dadhi]

Should improve #1 by faster compilation and tiny bit faster resolution, and less memory consumption. Because scoped service expression contains nested lambda.

[dadhi]

Here is the benchmark of duplicated (multiple) vs. de-duplicated (shared) nested lambda.
The sample expression is: () => new A(() => new X(new Y()), new B(() => new X(new Y()))) where
() => new X(new Y()) is duplicate: 5% faster and less memory too.