[code-reflection] RFR: Add support for local classes [v2]

[Maurizio Cimadamore]

> This PR adds support for local and anonymous instance class creation in the code model.
> 
> This is a bit trickier than inner classes in that local classes can also capture local variables from enclosing scopes. And, to make things even trickier, some local classes can be used in a *pre-construction* environment, that is in a location where `this` is not available yet (e.g. because we're in the middle of a `super` constructor call).
> 
> In this PR, we only add support for local and anonymous class that do **not** appear in a pre-construction context. The logic to compute the set of captured local is shared with `Lower` (as part of Java 8 that logic has been somewhat generalized to accommodate different clients, as lambda generation also needs to know the set of variables captured by a local class). The resulting captures are then added as arguments of the `new` operation, and the constructor signature is tweaked accordingly.
> 
> For instance, given this:
> 
> 
>     String testLocalCaptureParam(String s) {
>         class Foo {
>             String m() { return s; }
>         }
>         return new Foo().m();
>     }
> 
> 
> The following model is now generated:
> 
> 
> func @"testLocalCaptureParam" (%0 : LocalClassTest, %1 : java.lang.String)java.lang.String -> {
>                 %2 : Var<java.lang.String> = var %1 @"s";
>                 %3 : java.lang.String = var.load %2;
>                 %4 : .<LocalClassTest, LocalClassTest$2Foo> = new %0 %3 @"func<.<LocalClassTest, LocalClassTest$2Foo>, LocalClassTest, java.lang.String>";
>                 %5 : java.lang.String = invoke %4 @".<LocalClassTest, LocalClassTest$2Foo>::m()java.lang.String";
>                 return %5;
>             };
> 
> 
> I've added a bunch of tests to check the shape of the resulting code model, plus a dynamic test to make sure that we can indeed build local classes by interpreting said model.

Maurizio Cimadamore has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:

  Initial push

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Changes: https://git.openjdk.org/babylon/pull/111/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=111&range=01
  Stats: 367 lines in 7 files changed: 335 ins; 11 del; 21 mod
  Patch: https://git.openjdk.org/babylon/pull/111.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/111/head:pull/111

PR: https://git.openjdk.org/babylon/pull/111