[wasm][fuzzer] Clean up printing of locals types

Remove the hack introduced in https://crrev.com/c/2412176, use the
existing {ValueTypeToConstantName} function instead.

R=ahaas@chromium.org

Bug: chromium:1127717
Change-Id: I4ac50346825d7b00ea8dadccd7798a273ae84499
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2421568Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70028}

test/fuzzer/wasm-fuzzer-common.cc

@@ -273,10 +273,8 @@ void GenerateTestCase(Isolate* isolate, ModuleWireBytes wire_bytes,
         while (pos + count < locals && decls.type_list[pos + count] == type) {
           ++count;
         }
-        // TODO(wasm): Fix this for heap types.
-        std::string name = type.name();
-        name[0] = std::toupper(name[0]);
-        os << ".addLocals(kWasm" << name << ", " << count << ")";
+        os << ".addLocals(" << ValueTypeToConstantName(type) << ", " << count
+           << ")";
       }
       os << "\n";
     }