Fix setting breakpoint setting in await statements

runtime/vm/flow_graph_builder_test.cc

Index: runtime/vm/flow_graph_builder_test.cc
diff --git a/runtime/vm/flow_graph_builder_test.cc b/runtime/vm/flow_graph_builder_test.cc
index 122e6d4a834f781461dcf8d209ce99fdf2a1c30e..74a8562b21e1a6c2777d8d6720efec41890f9bbd 100644
--- a/runtime/vm/flow_graph_builder_test.cc
+++ b/runtime/vm/flow_graph_builder_test.cc
@@ -215,10 +215,7 @@ class SourcePositionTest : public ValueObject {
       BlockEntryInstr* entry = (*blocks_)[i];
       for (ForwardInstructionIterator it(entry); !it.Done(); it.Advance()) {
         Instruction* instr = it.Current();
-        TokenPosition token_pos = instr->token_pos();
-        if (token_pos.IsSynthetic()) {
-          token_pos = token_pos.FromSynthetic();
-        }
+        const TokenPosition token_pos = instr->token_pos().SourcePosition();
         if (!token_pos.IsReal()) {
           continue;
         }