[wasm][eh] Make delegating to an unwind block invalid

The delegate instruction is only allowed inside the try section of a try
block.

R=ahaas@chromium.org

Bug: chromium:1193169
Change-Id: I71756b18903dc39e487721b401d18bc4e213cbff
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2791565
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73720}

src/wasm/function-body-decoder-impl.h

@@ -2582,7 +2582,7 @@ class WasmFullDecoder : public WasmDecoder<validate> {
       return 0;
     }
     if (target->is_try_catch() || target->is_try_catchall() ||
-        target->is_try_catchall()) {
+        target->is_try_unwind()) {
       this->DecodeError(
           "cannot delegate inside the catch handler of the target");
     }

test/unittests/wasm/function-body-decoder-unittest.cc

@@ -2934,6 +2934,11 @@ TEST_F(FunctionBodyDecoderTest, TryDelegate) {
                  WASM_TRY_DELEGATE(WASM_STMTS(kExprThrow, ex), 0), kExprEnd},
                 kAppendEnd,
                 "cannot delegate inside the catch handler of the target");
+  ExpectFailure(sigs.v_v(),
+                {WASM_TRY_OP, kExprUnwind,
+                 WASM_TRY_DELEGATE(WASM_STMTS(kExprThrow, ex), 0), kExprEnd},
+                kAppendEnd,
+                "cannot delegate inside the catch handler of the target");
   ExpectFailure(
       sigs.v_v(),
       {WASM_BLOCK(WASM_TRY_OP, WASM_TRY_DELEGATE(WASM_STMTS(kExprThrow, ex), 3),