[wasm] Delete redundant enumeration definition

This CL solves recent clang compilation error:
"src/wasm/function-body-decoder.cc:1418:18: error: comparison of two
values with different enumeration types in switch statement
('v8::internal::wasm::ControlKind' and 'ControlKind')"

Bug: 
Change-Id: I6cb32bb3d42256a80d6f9222f5450ee93ce1021a
Reviewed-on: https://chromium-review.googlesource.com/615247Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47391}

src/wasm/function-body-decoder.cc

@@ -1399,23 +1399,17 @@ class WasmFullDecoder : public WasmDecoder {
         PrintF(" ");
         for (size_t i = 0; i < control_.size(); ++i) {
           Control* c = &control_[i];
-          enum ControlKind {
-            kControlIf,
-            kControlBlock,
-            kControlLoop,
-            kControlTry
-          };
           switch (c->kind) {
-            case kControlIf:
+            case v8::internal::wasm::kControlIf:
               PrintF("I");
               break;
-            case kControlBlock:
+            case v8::internal::wasm::kControlBlock:
               PrintF("B");
               break;
-            case kControlLoop:
+            case v8::internal::wasm::kControlLoop:
               PrintF("L");
               break;
-            case kControlTry:
+            case v8::internal::wasm::kControlTry:
               PrintF("T");
               break;
             default: