[wasm] Restrict expected frame types for {Code} objects.

The involved code kinds should no longer appear as part of frames for
{Code} objects since they have been moved to {WasmCode} for quite a
while now.

R=jkummerow@chromium.org

Change-Id: Iadc4ef668ebb56bf418fb706c3f118d9c3b553bd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1598755
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61347}

src/frames.cc

@@ -556,17 +556,16 @@ StackFrame::Type StackFrame::ComputeType(const StackFrameIteratorBase* iterator,
             return BUILTIN;
           case Code::OPTIMIZED_FUNCTION:
             return OPTIMIZED;
-          case Code::WASM_FUNCTION:
-          case Code::WASM_TO_CAPI_FUNCTION:
-            return WASM_COMPILED;
-          case Code::WASM_TO_JS_FUNCTION:
-            return WASM_TO_JS;
           case Code::JS_TO_WASM_FUNCTION:
             return JS_TO_WASM;
-          case Code::WASM_INTERPRETER_ENTRY:
-            return WASM_INTERPRETER_ENTRY;
           case Code::C_WASM_ENTRY:
             return C_WASM_ENTRY;
+          case Code::WASM_FUNCTION:
+          case Code::WASM_TO_CAPI_FUNCTION:
+          case Code::WASM_TO_JS_FUNCTION:
+          case Code::WASM_INTERPRETER_ENTRY:
+            // Never appear as on-heap {Code} objects.
+            UNREACHABLE();
           default:
             // All other types should have an explicit marker
             break;