Effects: add test on (de)serialization of contracts

- Add ContractDescriptorRenderer
- Add option to dump function contracts in DescriptorRendererOptions
- Add parsing of LANGUAGE_VERSION directive in AbstractLoadJava
- Add tests on serialization-deserializaton identity of contracts

==========
Introduction of EffectSystem: 13/18

compiler/testData/loadJava/compiledKotlinWithStdlib/contracts/recursion.txt

@@ -0,0 +1,4 @@
+package test
+
+public fun foo(/*0*/ n: kotlin.Int, /*1*/ x: kotlin.Any?): kotlin.Boolean
+    Returns(TRUE) -> x is String