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/deeplyNestedExpression.kt

@@ -0,0 +1,14 @@
+// LANGUAGE_VERSION: 1.3
+@file:Suppress("INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
+
+package test
+
+import kotlin.internal.contracts.*
+
+class A
+
+fun deeplyNested(x: Any?, y: Any?, b: Boolean, s: String?) {
+    contract {
+        returns(true) implies (((x is Int && x is String) || (x is Int && y is A) || b || (!b)) && s != null && (y is A || x is String))
+    }
+}