Updated native memory allocation profiling to use its own sample buffer instead of sharing a sample…

runtime/vm/source_report.cc

Index: runtime/vm/source_report.cc
diff --git a/runtime/vm/source_report.cc b/runtime/vm/source_report.cc
index cc3cf21b1cffa513a6a700f017909e2c892bb4c7..33911b1044789cadea2b78633cf911d3c3e27683 100644
--- a/runtime/vm/source_report.cc
+++ b/runtime/vm/source_report.cc
@@ -58,7 +58,8 @@ void SourceReport::Init(Thread* thread,
     // Build the profile.
     SampleFilter samplesForIsolate(thread_->isolate()->main_port(),
                                    Thread::kMutatorTask, -1, -1);
-    profile_.Build(thread, &samplesForIsolate, Profile::kNoTags);
+    profile_.Build(thread, &samplesForIsolate, Profiler::sample_buffer(),
+                   Profile::kNoTags);
   }
 }