Put native format ToString overrides under ifdef

[MichalStrehovsky]

I don't think anything calls these and because these are virtual, they cannot be trimmed.

Cc @dotnet/ilc-contrib

[Copilot]

Pull Request Overview

This PR optimizes the generated native format metadata reader by conditionally compiling ToString override methods under DEBUG preprocessor directives. The change prevents these virtual ToString methods from being included in release builds, improving code trimming efficiency since virtual methods cannot be trimmed by the compiler.

Key changes:

• Wrap all ToString override methods in #if DEBUG directives across handle types
• Update the code generator to emit the conditional compilation directives

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/coreclr/tools/Common/Internal/Metadata/NativeFormat/NativeFormatReaderGen.cs	Wraps existing ToString overrides in #if DEBUG directives for all handle types
src/coreclr/tools/Common/Internal/Metadata/NativeFormat/Generator/ReaderGen.cs	Updates the code generator to emit ToString methods under #if DEBUG

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[jkotas]

I assume that we want to keep GetHashCode/Equals since they are used or to avoid generating fallback support for them.

[MichalStrehovsky]

I assume that we want to keep GetHashCode/Equals since they are used or to avoid generating fallback support for them.

I'm not sure... I can make a PR that replaces them with throws and run CI on it.

Fallback support is generated either way because we don't have analysis for whether someone implemented GetHashCode as base.GetHashCode. (We literally had such code in the BCL during .NET Native times.)

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