Simplify native bridge skip check

A follow-up to r.android.com/1430136.

Test: CtsBionicTestCases
Bug: None
Change-Id: I372bc0866b1d286637d3671f82be83cec1027bca
diff --git a/tests/utils.h b/tests/utils.h
index c1b7f65..acd8bc6 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -78,13 +78,8 @@
 
 static inline bool running_with_native_bridge() {
 #if defined(__BIONIC__)
-#if defined(__arm__)
-  static const prop_info* pi = __system_property_find("ro.dalvik.vm.isa.arm");
+  static const prop_info* pi = __system_property_find("ro.dalvik.vm.isa." ABI_STRING);
   return pi != nullptr;
-#elif defined(__aarch64__)
-  static const prop_info* pi = __system_property_find("ro.dalvik.vm.isa.arm64");
-  return pi != nullptr;
-#endif
 #endif
   return false;
 }