ios,build: disable v8 trap handler-inside-posix

This is backporting a commit in a future version of V8, hence this
is not a nodejs-mobile patch for future versions of Node.js.

deps/v8/src/trap-handler/handler-inside-posix.cc

@@ -47,6 +47,8 @@ namespace v8 {
 namespace internal {
 namespace trap_handler {
 
+#if V8_TRAP_HANDLER_SUPPORTED
+
 #if V8_OS_LINUX
 #define CONTEXT_REG(reg, REG) &uc->uc_mcontext.gregs[REG_##REG]
 #elif V8_OS_DARWIN
@@ -181,6 +183,8 @@ void HandleSignal(int signum, siginfo_t* info, void* context) {
   // TryHandleSignal modifies context to change where we return to.
 }
 
+#endif
+
 }  // namespace trap_handler
 }  // namespace internal
 }  // namespace v8