Fix calling existing ctor with MethodInvoker; share tests with invokers

[steveharter]

Refactored the existing MethodInfo\ConstructorInfo tests so they can also run under the new invoker classes MethodInvoker\ConstructorInvoker; they are run in both a forced-interpreted and a forced-emit mode for additional coverage.

This uncovered two edge case issues (fixed in this PR) that only affect the new invoker classes that were added in Preview 7:

• Calling a constructor on an existing instance with a MethodInvoker now works as expected: the obj parameter's constructor is invoked and null is returned; this is consistent with ConstructorInfo.Invoke(obj, ...)
• Calling a constructor invoker on abstract base class or attempting to call static constructor will now always throw MemberAccessException (same exception type used for similar cases). Calling static constructors can still be done with ConstructorInfo but since that is rare, adds overhead, and is not supported on NativeAOT, support wasn't added to MethodInvoker or ConstructorInvoker.

No tests were removed except for the invoker test "ExistingInstance()" which was already covered in the shared tests.

These changes should be ported to v8\RC2 since they only affect the new APIs added in Preview 7 and will avoid a breaking change in v9.

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Issue Details

---

[verifying tests]

Author:	steveharter
Assignees:	steveharter
Labels:	area-System.Reflection
Milestone:	-

[jkotas]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jkotas]

LGTM (Please check that the affected tests are passing in the extra-platforms legs before merging.)

[steveharter]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[steveharter]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[steveharter]

CI failures in runtime-extra-platforms appear consistent with other recent PRs including #90836 and #90864.

Created some known issues to help filter the errors in the future. Also, there's some infra work needed so failures running runtime-extra-platforms show all of the unknown failures (currently just the first 4 are shown).

[steveharter]

/backport to release/8.0

[jkotas]

/backport to release/8.0

[github-actions]

Started backporting to release/8.0: https://github.com/dotnet/runtime/actions/runs/5945904726