Optimize external overridability conditions

- Skip ones that can lead only to success after first success
- And vice versa

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/BuiltinOverridabilityCondition.kt

@@ -64,4 +64,6 @@ class BuiltinOverridabilityCondition : ExternalOverridabilityCondition {
         // incompatible override
         return Result.INCOMPATIBLE
     }
+
+    override fun getContract() = ExternalOverridabilityCondition.Contract.CONFLICTS_ONLY
 }

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/ErasedOverridabilityCondition.kt

@@ -43,4 +43,6 @@ class ErasedOverridabilityCondition : ExternalOverridabilityCondition {
             else ->  Result.UNKNOWN
         }
     }
+
+    override fun getContract() = ExternalOverridabilityCondition.Contract.SUCCESS_ONLY
 }

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/FieldOverridabilityCondition.kt

@@ -33,4 +33,6 @@ class FieldOverridabilityCondition : ExternalOverridabilityCondition {
 
         return Result.UNKNOWN
     }
+
+    override fun getContract() = ExternalOverridabilityCondition.Contract.BOTH
 }