Fix false-positive ArrayPtr dispose warning

[johnml1135]

Summary

Suppress the ArrayPtr finalizer warning for non-owning wrappers such as ArrayPtr.Null while preserving the warning for managed-owned unmanaged buffers.

Why

FieldWorks debug sessions were reporting a misleading "Missing Dispose() call for ArrayPtr" message at shutdown even when the finalized ArrayPtr instance did not own unmanaged memory.

Validation

• Rebuilt the local liblcm net462 runtime overlay
• Verified the updated SIL.LCModel DLL and PDB files were copied into FieldWorks Output/Debug
• Confirmed the change is limited to ArrayPtr warning behavior

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This change is 

[Copilot]

Pull request overview

This PR refines ArrayPtr’s finalizer-time debug warning so shutdown logs don’t report “Missing Dispose()” for wrapper instances that do not own unmanaged memory (e.g., ArrayPtr.Null), while keeping the warning for instances responsible for freeing unmanaged buffers.

Changes:

• Remove legacy commented-out “hack” related to excluding the null instance from finalizer behavior.
• Gate the “Missing Dispose()” Debug.WriteLineIf warning on m_ownMemory to avoid warning for non-owning wrappers.

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[Copilot]

The new warning condition uses m_ownMemory, but m_ownMemory == true does not necessarily mean unmanaged memory was actually allocated (e.g., new ArrayPtr() sets m_ownMemory = true while m_ptr is still IntPtr.Zero until Resize is called). As written, finalized instances created via the default ctor but never allocated could still emit the warning, which contradicts the new comment and can still produce false positives. Consider including an allocation check (e.g., m_ptr != IntPtr.Zero / m_Size >= 0) or adjust the comment to match the actual condition.

Suggested change

	Debug.WriteLineIf(!disposing && m_ownMemory,
	Debug.WriteLineIf(!disposing && m_ownMemory && m_ptr != IntPtr.Zero,

[jasonleenaylor]

@jasonleenaylor reviewed 1 file and all commit messages, and made 1 comment.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on johnml1135).