Don't set RUBY_TYPED_EMBEDDABLE flag on backtrace

vm_backtrace.c

@@ -540,7 +540,10 @@ static const rb_data_type_t backtrace_data_type = {
         NULL, // No external memory to report,
         backtrace_update,
     },
-    0, 0, RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_WB_PROTECTED | RUBY_TYPED_EMBEDDABLE
+    /* Cannot set the RUBY_TYPED_EMBEDDABLE flag because the loc of frame_info
+     * points elements in the backtrace array. This can cause the loc to become
+     * incorrect if this backtrace object is moved by compaction. */
+    0, 0, RUBY_TYPED_FREE_IMMEDIATELY | RUBY_TYPED_WB_PROTECTED
 };
 
 int