Issue 6578. Report warning, not error for static/instance getter/setter mismatch

compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java

Index: compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
diff --git a/compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java b/compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
index 16d1e639a6d9fce9f7e9140d505cad5e855a30c6..550ea7e65b978e2ae52d598920e56c9b2229490d 100644
--- a/compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
+++ b/compiler/java/com/google/dart/compiler/resolver/ResolverErrorCode.java
@@ -118,7 +118,7 @@ public enum ResolverErrorCode implements ErrorCode {
   FACTORY_CANNOT_BE_CONST("A factory cannot be const"),
   FIELD_DOES_NOT_HAVE_A_GETTER(ErrorSeverity.WARNING, "Field does not have a getter"),
   FIELD_DOES_NOT_HAVE_A_SETTER(ErrorSeverity.WARNING, "Field does not have a setter"),
-  FIELD_GETTER_SETTER_SAME_STATIC("Field's getter and setter should be both static or not static"),
+  FIELD_GETTER_SETTER_SAME_STATIC(ErrorSeverity.WARNING, "Field's getter and setter should be both static or not static"),
   FINAL_FIELD_MUST_BE_INITIALIZED("The final field %s must be initialized"),
   FORMAL_PARAMETER_NAME_EXPECTED("Formal parameter name expected"),
   // TODO(zundel): error message needs JUnit test - how to test #imports in junit?