Fix 'equals' for NotNullBasicValue

NotNullBasicValues were merged incorrectly sometimes,
which caused problems with INSTANCEOF checks.

 #KT-18779 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/nullCheck/nullabilityValues.kt

@@ -23,7 +23,7 @@ import org.jetbrains.org.objectweb.asm.Type
 import org.jetbrains.org.objectweb.asm.tree.analysis.BasicValue
 
 class NotNullBasicValue(type: Type?) : StrictBasicValue(type) {
-    override fun equals(other: Any?): Boolean = other is NotNullBasicValue
+    override fun equals(other: Any?): Boolean = other is NotNullBasicValue && other.type == type
     // We do not differ not-nullable values, so we should always return the same hashCode
     // Actually it doesn't really matter because analyzer is not supposed to store values in hashtables
     override fun hashCode() = 0