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/multieffectContracts.kt

@@ -0,0 +1,44 @@
+// LANGUAGE_VERSION: 1.3
+@file:Suppress("INVISIBLE_MEMBER", "INVISIBLE_REFERENCE")
+
+package test
+
+import kotlin.internal.contracts.*
+
+fun twoReturnsValue(b: Boolean) {
+    contract {
+        returns(true) implies b
+        returns(false) implies (!b)
+    }
+}
+
+fun threeReturnsValue(b: Boolean) {
+    contract {
+        returnsNotNull() implies (b != null)
+        returns(true) implies (b)
+        returns(false) implies (!b)
+    }
+}
+
+fun returnsAndFinished(b: Boolean) {
+    contract {
+        returns(true) implies (b)
+        returns() implies (b != null)
+        returns(false) implies (!b)
+    }
+}
+
+fun returnsAndCalls(b: Boolean, block: () -> Unit) {
+    contract {
+        returns(false) implies (!b)
+        callsInPlace(block)
+        returns(true) implies (b)
+    }
+}
+
+fun severalCalls(x: () -> Unit, y: () -> Unit) {
+    contract {
+        callsInPlace(x, InvocationKind.AT_MOST_ONCE)
+        callsInPlace(y, InvocationKind.AT_LEAST_ONCE)
+    }
+}