runtime/cgo: enable arm64 EXC_BAD_ACCESS handler

Change-Id: I8e912ff9327a4163b63b8c628aa3546e86ddcc02
Reviewed-on: https://go-review.googlesource.com/8983Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

src/runtime/cgo/gcc_darwin_arm64.c

@@ -86,6 +86,8 @@ threadentry(void *v)
 	ts = *(ThreadStart*)v;
 	free(v);
 
+	darwin_arm_init_thread_exception_port();
+
 	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
 	return nil;
 }
@@ -148,5 +150,8 @@ x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 	// yes, tlsbase from mrs might not be correctly aligned.
 	inittls(tlsg, (void**)((uintptr)tlsbase & ~7));
 
+	darwin_arm_init_mach_exception_handler();
+	darwin_arm_init_thread_exception_port();
+
 	init_working_dir();
 }