LibJS: Surround the VM parameter of TRY_OR_THROW_OOM with parentheses

Depending on how this is invoked, the preprocessor may get confused when
pasting the VM parameter into this expression. For example, it trips up
on the JS REPL in cases such as:

    TRY_OR_THROW_OOM(*g_vm, ...);

Userland/Libraries/LibJS/Runtime/Completion.h

@@ -24,7 +24,7 @@ namespace JS {
             auto&& _temporary_result = (expression));                                                \
         if (_temporary_result.is_error()) {                                                          \
             VERIFY(_temporary_result.error().code() == ENOMEM);                                      \
-            return vm.throw_completion<JS::InternalError>(JS::ErrorType::OutOfMemory);               \
+            return (vm).throw_completion<JS::InternalError>(JS::ErrorType::OutOfMemory);             \
         }                                                                                            \
         static_assert(!::AK::Detail::IsLvalueReference<decltype(_temporary_result.release_value())>, \
             "Do not return a reference from a fallible expression");                                 \