Use CodeSourceMap for stack traces (still JIT only).

runtime/vm/flow_graph_compiler_mips.cc

Index: runtime/vm/flow_graph_compiler_mips.cc
diff --git a/runtime/vm/flow_graph_compiler_mips.cc b/runtime/vm/flow_graph_compiler_mips.cc
index b6914ad6b2eb223121bf8df33dbe6b48327db84c..7854b08c4313a13d575c88a5f8775290414808a9 100644
--- a/runtime/vm/flow_graph_compiler_mips.cc
+++ b/runtime/vm/flow_graph_compiler_mips.cc
@@ -1287,9 +1287,8 @@ void FlowGraphCompiler::EmitMegamorphicInstanceCall(
     if (try_index == CatchClauseNode::kInvalidTryIndex) {
       try_index = CurrentTryIndex();
     }
-    pc_descriptors_list()->AddDescriptor(
-        RawPcDescriptors::kOther, assembler()->CodeSize(), Thread::kNoDeoptId,
-        token_pos, try_index);
+    AddDescriptor(RawPcDescriptors::kOther, assembler()->CodeSize(),
+                  Thread::kNoDeoptId, token_pos, try_index);
   } else if (is_optimizing()) {
     AddCurrentDescriptor(RawPcDescriptors::kOther, Thread::kNoDeoptId,
                          token_pos);