Switch default JVM target to 1.8

#KT-29405 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/OriginCollectingClassBuilderFactory.kt

@@ -58,7 +58,7 @@ class OriginCollectingClassBuilderFactory(private val builderMode: ClassBuilderM
     }
 
     override fun asBytes(builder: ClassBuilder): ByteArray {
-        val classWriter = ClassWriter(0)
+        val classWriter = ClassWriter(ClassWriter.COMPUTE_FRAMES or ClassWriter.COMPUTE_MAXS)
         (builder as OriginCollectingClassBuilder).classNode.accept(classWriter)
         return classWriter.toByteArray()
     }
@@ -66,4 +66,4 @@ class OriginCollectingClassBuilderFactory(private val builderMode: ClassBuilderM
     override fun asText(builder: ClassBuilder) = throw UnsupportedOperationException()
 
     override fun close() {}
-}
+}