Add few tests for contracts

- Contracts in getter/setter (unexpected behaviour)
- Check smartcasts when non-null assertion for a contract function is used
- Check work of contracts when type parameter of the callsInPlace is specify explicitly
- Check smartcasts working if type checking for contract function is used

compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/controlFlow/initialization/pos/7.kt

@@ -0,0 +1,52 @@
+// !LANGUAGE: +AllowContractsForCustomFunctions +UseCallsInPlaceEffect
+// !USE_EXPERIMENTAL: kotlin.contracts.ExperimentalContracts
+
+/*
+ KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (POSITIVE)
+
+ SECTION: contracts
+ CATEGORIES: analysis, controlFlow, initialization
+ NUMBER: 7
+ DESCRIPTION: Check initialization when type parameter of the callsInPlace is specify explicitly.
+ */
+
+// FILE: contracts.kt
+
+package contracts
+
+import kotlin.contracts.*
+
+inline fun <T> case_1(block: () -> T): T {
+    contract {
+        callsInPlace<T>(block, InvocationKind.EXACTLY_ONCE)
+    }
+    return block()
+}
+
+inline fun case_2(block: () -> Int): Int {
+    contract {
+        callsInPlace<Number>(block, InvocationKind.EXACTLY_ONCE)
+    }
+    return block()
+}
+
+// FILE: usages.kt
+
+import contracts.*
+
+fun case_1() {
+    val value_1: Int
+    case_1 {
+        value_1 = 10
+    }
+    println(value_1)
+}
+
+fun case_2() {
+    val value_1: Int
+    case_2 {
+        value_1 = 10
+        10
+    }
+    println(value_1)
+}

compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/controlFlow/initialization/pos/7.txt

@@ -0,0 +1,13 @@
+package
+
+public fun case_1(): kotlin.Unit
+public fun case_2(): kotlin.Unit
+
+package contracts {
+    public inline fun </*0*/ T> case_1(/*0*/ block: () -> T): T
+        CallsInPlace(block, EXACTLY_ONCE)
+
+    public inline fun case_2(/*0*/ block: () -> kotlin.Int): kotlin.Int
+        CallsInPlace(block, EXACTLY_ONCE)
+
+}