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

runtime/vm/flow_graph_compiler_arm.cc

Index: runtime/vm/flow_graph_compiler_arm.cc
diff --git a/runtime/vm/flow_graph_compiler_arm.cc b/runtime/vm/flow_graph_compiler_arm.cc
index a8433c2c5c28ce89d6a744242038490be045ea95..c1eb50cd7b5a61464c3403013be03eb8527a3c6f 100644
--- a/runtime/vm/flow_graph_compiler_arm.cc
+++ b/runtime/vm/flow_graph_compiler_arm.cc
@@ -1408,7 +1408,7 @@ Condition FlowGraphCompiler::EmitEqualityRegConstCompare(
       __ BranchLinkPatchable(
           *StubCode::UnoptimizedIdenticalWithNumberCheck_entry());
     }
-    if (token_pos != Scanner::kNoSourcePos) {
+    if (token_pos >= 0) {
       AddCurrentDescriptor(RawPcDescriptors::kRuntimeCall,
                            Thread::kNoDeoptId,
                            token_pos);
@@ -1437,7 +1437,7 @@ Condition FlowGraphCompiler::EmitEqualityRegRegCompare(Register left,
       __ BranchLinkPatchable(
           *StubCode::UnoptimizedIdenticalWithNumberCheck_entry());
     }
-    if (token_pos != Scanner::kNoSourcePos) {
+    if (token_pos >= 0) {
       AddCurrentDescriptor(RawPcDescriptors::kRuntimeCall,
                            Thread::kNoDeoptId,
                            token_pos);