EnC API for method instrumentation

[tmat]

Background and Motivation

Enables instrumentation of methods using EnC updates.

See #66768

Proposed API

namespace Microsoft.CodeAnalysis.Emit;

+ public readonly struct MethodInstrumentation
+ {
+     /// <summary>
+     /// Kinds of instrumentation to apply to the entire method body.
+     /// </summary>
+     public ImmutableArray<InstrumentationKind> Kinds { get; init; }
+ }

public enum InstrumentationKind
{
     None = 0,
     TestCoverage = 1,

+    /// <summary>
+    /// Instruments the code to trace local variable writes.
+    /// </summary>
+    LocalStateTracing = 2,
}

public readonly struct SemanticEdit
{
+    /// <summary>
+    ///  Instrumentation update to be applied to a method.
+    /// <see cref="OldSymbol"/> and <see cref="NewSymbol"/> must be non-null <see cref="IMethodSymbol"/>s.
+    /// <see cref="Kind"/> must be <see cref="SemanticEditKind.Update"/>.
+    /// </summary>
+    public MethodInstrumentation Instrumentation { get; }

-    public SemanticEdit(SemanticEditKind kind, ISymbol? oldSymbol, ISymbol? newSymbol, Func<SyntaxNode, SyntaxNode?>? syntaxMap, bool preserveLocalVariables)

+    public SemanticEdit(SemanticEditKind kind, ISymbol? oldSymbol, ISymbol? newSymbol, Func<SyntaxNode, SyntaxNode?>? syntaxMap = null, bool preserveLocalVariables = false, MethodInstrumentation instrumentation = default)
}

[333fred]

API Review

• The removal needs to be just removing the default parameters and adding EditorBrowsable.Never, like we do for the rest of our compat shims
• Otherwise, looks good.

Approved.