ART: Remove thread dump

Remove the thread dump from JniAbort. Newer handling of the abort
message means it will be duplicated in the message and the abort
handler/tombstoned.

Bug: 120506942
Test: m test-art-host
Change-Id: Ib9556d78da7daaaf59880a03e144a1839dcb3fce
diff --git a/runtime/jni/java_vm_ext.cc b/runtime/jni/java_vm_ext.cc
index a61a48a..7a9d292 100644
--- a/runtime/jni/java_vm_ext.cc
+++ b/runtime/jni/java_vm_ext.cc
@@ -535,8 +535,6 @@
   if (current_method != nullptr) {
     os << "\n    from " << current_method->PrettyMethod();
   }
-  os << "\n";
-  self->Dump(os);
 
   if (check_jni_abort_hook_ != nullptr) {
     check_jni_abort_hook_(check_jni_abort_hook_data_, os.str());