Resolve initialization order fiasco between code_descriptors.cc and token_position.cc.

runtime/vm/token_position.h

Index: runtime/vm/token_position.h
diff --git a/runtime/vm/token_position.h b/runtime/vm/token_position.h
index 65dd3ed353eff1f555b41fef6bf97c2135c79f55..c28f9a49661aec95371f85ecd2654fc8f23d5d71 100644
--- a/runtime/vm/token_position.h
+++ b/runtime/vm/token_position.h
@@ -79,10 +79,14 @@ class TokenPosition {
 
   static const intptr_t kMaxSentinelDescriptors = 64;
 
-#define DECLARE_VALUES(name, value) static const TokenPosition k##name;
+#define DECLARE_VALUES(name, value)                                            \
+  static const intptr_t k##name##Pos = value;                                  \
+  static const TokenPosition k##name;
   SENTINEL_TOKEN_DESCRIPTORS(DECLARE_VALUES);
 #undef DECLARE_VALUES
+  static const intptr_t kMinSourcePos = 0;
   static const TokenPosition kMinSource;
+  static const intptr_t kMaxSourcePos = kSmiMax32 - kMaxSentinelDescriptors - 2;
   static const TokenPosition kMaxSource;
 
   // Decode from a snapshot.
@@ -110,11 +114,6 @@ class TokenPosition {
     return value_;
   }
 
-  // Token position constants.
-  static const intptr_t kNoSourcePos = -1;
-  static const intptr_t kMinSourcePos = 0;
-  static const intptr_t kMaxSourcePos = kSmiMax32 - kMaxSentinelDescriptors - 2;
-
   // Is |this| a classifying sentinel source position?
   // Classifying positions are used by the profiler to group instructions whose
   // cost isn't naturally attributable to a source location.