[wasm] Remove some redundant/unnecessary DisallowHeapAllocation scopes

R=mstarzinger@chromium.org

Change-Id: I57ff09601a9e84cc5b53ff06a446b7dfc3c026b2
Reviewed-on: https://chromium-review.googlesource.com/1032742Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52940}

src/wasm/module-compiler.cc

@@ -486,7 +486,6 @@ class IndirectPatcher {
 
 ModuleEnv CreateModuleEnvFromCompiledModule(
     Isolate* isolate, Handle<WasmCompiledModule> compiled_module) {
-  DisallowHeapAllocation no_gc;
   WasmModule* module = compiled_module->shared()->module();
   wasm::UseTrapHandler use_trap_handler =
       compiled_module->GetNativeModule()->use_trap_handler() ? kUseTrapHandler
@@ -728,7 +727,6 @@ const wasm::WasmCode* LazyCompileDirectCall(Isolate* isolate,
 
   int patched = 0;
   {
-    DisallowHeapAllocation no_gc;
     // Now patch the code in {wasm_caller} with all functions which are now
     // compiled. This will pick up any other compiled functions, not only {ret}.
     size_t pos = 0;

src/wasm/wasm-objects.cc

@@ -901,7 +901,6 @@ WasmExportedFunction* WasmExportedFunction::cast(Object* object) {
 }
 
 WasmInstanceObject* WasmExportedFunction::instance() {
-  DisallowHeapAllocation no_allocation;
   Handle<Symbol> symbol(GetIsolate()->factory()->wasm_instance_symbol());
   MaybeHandle<Object> result =
       JSObject::GetPropertyOrElement(handle(this), symbol);
@@ -909,7 +908,6 @@ WasmInstanceObject* WasmExportedFunction::instance() {
 }
 
 int WasmExportedFunction::function_index() {
-  DisallowHeapAllocation no_allocation;
   Handle<Symbol> symbol = GetIsolate()->factory()->wasm_function_index_symbol();
   MaybeHandle<Object> result =
       JSObject::GetPropertyOrElement(handle(this), symbol);