Do checks on the fault address when we think it's an NPE.

bug:29321958
Change-Id: I28f4da56eb3e0b48721d3ac41114858bc80daadb
diff --git a/runtime/entrypoints/quick/quick_default_externs.h b/runtime/entrypoints/quick/quick_default_externs.h
index 771e143..d0dad34 100644
--- a/runtime/entrypoints/quick/quick_default_externs.h
+++ b/runtime/entrypoints/quick/quick_default_externs.h
@@ -120,6 +120,7 @@
 extern "C" void art_quick_throw_div_zero();
 extern "C" void art_quick_throw_no_such_method(int32_t method_idx);
 extern "C" void art_quick_throw_null_pointer_exception();
+extern "C" void art_quick_throw_null_pointer_exception_from_signal(uintptr_t address);
 extern "C" void art_quick_throw_stack_overflow(void*);
 extern "C" void art_quick_throw_string_bounds(int32_t index, int32_t limit);