[wasm] Refactor encoder.h to use a proper buffer and remove OldFunctions section.

test/cctest/wasm/test-wasm-function-name-table.cc

Index: test/cctest/wasm/test-wasm-function-name-table.cc
diff --git a/test/cctest/wasm/test-wasm-function-name-table.cc b/test/cctest/wasm/test-wasm-function-name-table.cc
index cce131d9ff79e6c2a195ab3613550acf8a4629ad..1ae78dcb4e6d8322dc1efb06861bb1e92d49b537 100644
--- a/test/cctest/wasm/test-wasm-function-name-table.cc
+++ b/test/cctest/wasm/test-wasm-function-name-table.cc
@@ -41,9 +41,9 @@ void testFunctionNameTable(Vector<Vector<const char>> names) {
                      name.start() + name.length());
     // Make every second function name null-terminated.
     if (func_index % 2) all_names.push_back('\0');
-    module.functions.push_back(
-        {nullptr, 0, 0, static_cast<uint32_t>(name_offset),
-         static_cast<uint32_t>(name.length()), 0, 0, false});
+    module.functions.push_back({nullptr, 0, 0,
+                                static_cast<uint32_t>(name_offset),
+                                static_cast<uint32_t>(name.length()), 0, 0});
     ++func_index;
   }