Don't test directly against Scanner::kNoSourcePos instead use >= 0.

runtime/vm/flow_graph_compiler_ia32.cc

Index: runtime/vm/flow_graph_compiler_ia32.cc
diff --git a/runtime/vm/flow_graph_compiler_ia32.cc b/runtime/vm/flow_graph_compiler_ia32.cc
index e9b180820a2cce8ad82032e56540268da39a607f..e3b0fcf41cc5b1783c3de820e09dd698c0de4b21 100644
--- a/runtime/vm/flow_graph_compiler_ia32.cc
+++ b/runtime/vm/flow_graph_compiler_ia32.cc
@@ -1369,7 +1369,7 @@ Condition FlowGraphCompiler::EmitEqualityRegConstCompare(
     } else {
       __ Call(*StubCode::UnoptimizedIdenticalWithNumberCheck_entry());
     }
-    if (token_pos != Scanner::kNoSourcePos) {
+    if (token_pos >= 0) {
       AddCurrentDescriptor(RawPcDescriptors::kRuntimeCall,
                            Thread::kNoDeoptId,
                            token_pos);
@@ -1396,7 +1396,7 @@ Condition FlowGraphCompiler::EmitEqualityRegRegCompare(Register left,
     } else {
       __ Call(*StubCode::UnoptimizedIdenticalWithNumberCheck_entry());
     }
-    if (token_pos != Scanner::kNoSourcePos) {
+    if (token_pos >= 0) {
       AddCurrentDescriptor(RawPcDescriptors::kRuntimeCall,
                            Thread::kNoDeoptId,
                            token_pos);