KT-12152 : constructor consistency analysis, base cases

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

@@ -0,0 +1,10 @@
+val instance = My()
+
+class My {
+    val equalsInstance = (<!DEBUG_INFO_LEAKING_THIS!>this<!> == instance)
+
+    val isInstance = if (this === instance) "true" else "false"
+
+    override fun equals(other: Any?) =
+            other is My && isInstance.hashCode() == <!DEBUG_INFO_SMARTCAST!>other<!>.isInstance.hashCode()
+}