Add [DebuggerStepThrough] to MulticastDelegate constructors.

[chuckries]

Adding [DebuggerStepThrough] to these constructors allows debuggers to avoid stepping into them and stopping regardless of Just My Code settings. This is desirable for debuggers as there is little benefit to stopping in these constructors as they are primarily infrastructure inserted by the compiler.

[ghost]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[chuckries]

fixes #77131

[ghost]

Tagging subscribers to this area: @tommcdon
See info in area-owners.md if you want to be subscribed.

Issue Details

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Adding [DebuggerStepThrough] to these constructors allows debuggers to avoid stepping into them and stopping regardless of Just My Code settings. This is desirable for debuggers as there is little benefit to stopping in these constructors as they are primarily infrastructure inserted by the compiler.

Author:	chuckries
Assignees:	-
Labels:	area-Diagnostics-coreclr, community-contribution
Milestone:	-

[tommcdon]

LGTM - adding @noahfalk @hoyosjs for additional review

[tommcdon]

Adding @thaystg @lambdageek for awareness and in case something similar should be done for mono

[tommcdon]

LGTM. I've added a few other folks for additional review.

[hoyosjs]

All issues are known (cc: @missymessa @AlitzelMendez @ulisesh @markwilkie, since the check tab is still red...), so merging this one.

[ulisesh]

Thanks for the heads up @hoyosjs, the check is red by design. We are still deciding if we want to make the check green if all failures are known. Something interesting about the generated check is that the failures are shown as infrastructure failures but they look like test issues to me. I'll investigate what happened