Port the runtime and translator fixes from upstream's KartPad batch

From patchzyy/Wiicompiled 6f14bde (#244), runtime and translator parts only:
- Keep KD and NCD devices available while networking is off; only IP and
  SSL need the network.
- Run RFLiIsWorking's alarm pump in a private interrupt context so callback
  register writes don't clobber the caller, and release the alarm recursion
  guard before rescheduling.
- Share one LR continuation dispatch per translated function when it has
  several continuation calls.

The renderer half of that commit is left out: it conflicts with the stereo
renderer, and upstream reverted part of it (e409d9f) for stutters.

(cherry picked from part of commit 6f14bde26a4ed6390d4f18e1b3a9c1be6819d589)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011tcyLz63pXjoYEwsFjfg8F

translator/tests/Translator.Tests/SharedLrContinuationCodeGenTests.cs

@@ -0,0 +1,52 @@
+using Translator.Core.Analysis.Ssa;
+using Translator.Core.Analysis.Representation;
+using Translator.Core.CodeGen;
+using Translator.Core.Ir;
+using Translator.Core.Representation;
+using Xunit;
+
+namespace Translator.Tests;
+
+public class SharedLrContinuationCodeGenTests
+{
+    [Theory]
+    [InlineData(2)]
+    [InlineData(20)]
+    public void MultipleHooksShareOneCompleteDispatchAndKeepNormalFallthrough(int callCount)
+    {
+        var instructions = new List<IrInstruction>();
+        for (var i = 0; i < callCount; i++)
+        {
+            instructions.Add(new IrAssign("lr", IrValue.Imm(unchecked((int)(0x80001004u + (uint)i * 4u)))));
+            instructions.Add(new IrCall(string.Empty, "0x81800000", Array.Empty<IrValue>()));
+        }
+        instructions.Add(new IrAssign("r3", IrValue.Imm(8)));
+        instructions.Add(new IrReturn(null));
+        var function = new IrFunction("shared_lr_continuation", "0x80001000", new[]
+        {
+            new IrBasicBlock("0x80001000", instructions),
+            new IrBasicBlock("0x80001100", new IrInstruction[]
+            {
+                new IrAssign("r3", IrValue.Imm(1)), new IrReturn(null)
+            })
+        });
+        var types = new RepresentationEnvironment(new Dictionary<string, ValueRepresentation>
+        {
+            ["lr"] = ValueRepresentation.UInt32, ["r3"] = ValueRepresentation.UInt32
+        });
+        var code = new CxxLinearCodeGenerator().Emit(0x80001000,
+            new SsaTransformer().Convert(function),
+            new FunctionAbiClassification("shared_lr_continuation", ValueRepresentation.Void), types,
+            lrContinuationCallTargets: new HashSet<uint> { 0x81800000u });
+
+        Assert.Equal(1, code.Split("switch (ctx->lr)").Length - 1);
+        Assert.Equal(callCount, code.Split("goto lr_continuation_dispatch;").Length - 1);
+        Assert.Equal(callCount, code.Split("if (ctx->lr != ").Length - 1);
+        Assert.Contains("case 0x80001100u:", code);
+        Assert.Contains("goto loc_80001100;", code);
+        Assert.Contains("InvokeIndirectCpu(ctx->lr, ctx);", code);
+        var sharedLabel = code.IndexOf("lr_continuation_dispatch:", StringComparison.Ordinal);
+        Assert.True(code.IndexOf("r3 = 8;", StringComparison.Ordinal) < sharedLabel);
+        Assert.True(code.IndexOf("case 0x80001100u:", StringComparison.Ordinal) > sharedLabel);
+    }
+}