Description

Removes the eager check in COMDelegate::GetDelegateCtor that throws NotSupportedException when attempting to create a delegate to a method with [UnmanagedCallersOnly]. This check is inconsistent with the runtime's policy of lazy validation for UnmanagedCallersOnly methods, which failfast only when actually invoked (e.g., via reflection or calli).

Changes:

• Removed HasUnmanagedCallersOnlyAttribute() check and exception throw from comdelegate.cpp:2796-2801
• Removed NegativeTest_ViaDelegate test that verified this exception behavior
• Removed unused IL methods GetDoubleDelegate and ManagedDoubleCallback from test infrastructure
• Removed unused resource string NotSupported_UnmanagedCallersOnlyTarget from Strings.resx

Behavior change:

// Before: throws NotSupportedException during delegate creation
var del = new Func<int, int>(MyUnmanagedCallersOnlyMethod);

// After: delegate creation succeeds, failfast occurs on invocation (consistent with reflection path)
var del = new Func<int, int>(MyUnmanagedCallersOnlyMethod);
del(42); // failfast here

Customer Impact

Minimal. The previous exception could be worked around, and invoking an UnmanagedCallersOnly method via delegate already triggers failfast at call time. This aligns the fast delegate construction path with the existing slow path behavior.

Regression

No. Removes a safety check introduced earlier but makes behavior consistent across all delegate construction paths.

Testing

CoreCLR and libraries builds verified. Remaining UnmanagedCallersOnly tests ensure failfast behavior on invocation still works correctly.

Risk

Low. Change removes defensive check but failfast protection remains at invocation time, consistent with other code paths.

• Fixes Delegate fast path construction checks for [UnmanagedCallersOnly] attribute #122890

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