Ease field initialization check

Since there is already VAL_REASSIGNMENT diagnostics, we can safely only
for direct assignments.
 #KT-40893 Fixed

compiler/testData/codegen/box/contracts/listAppend.kt

@@ -0,0 +1,28 @@
+// !USE_EXPERIMENTAL: kotlin.contracts.ExperimentalContracts
+// IGNORE_BACKEND: NATIVE
+// WITH_RUNTIME
+// KJS_WITH_FULL_RUNTIME
+
+import kotlin.contracts.*
+
+class A {
+    val value = arrayListOf("O")
+
+    init {
+        foo {
+            value += "K"
+        }
+    }
+}
+
+fun foo(block: () -> Unit) {
+    contract {
+        callsInPlace(block, InvocationKind.EXACTLY_ONCE)
+    }
+    block()
+}
+
+fun box(): String {
+    val a = A()
+    return if (a.value == listOf("O", "K"))  "OK" else "FAIL"
+}