KT-12152 : constructor consistency analysis, base cases

compiler/testData/diagnostics/tests/constructorConsistency/init.kt

@@ -0,0 +1,9 @@
+class My {
+    val x: String
+
+    init {
+        x = <!DEBUG_INFO_LEAKING_THIS!>foo<!>()
+    }
+
+    fun foo(): String = x
+}