Condition of 'if' expression is constant: report enum entries comparison

#KT-28803 Fixed

idea/testData/inspectionsLocal/constantConditionIf/enumEntryEq2.kt

@@ -0,0 +1,6 @@
+// PROBLEM: Condition is always 'true'
+fun foo(x: Int) {}
+
+fun bar() {
+    foo(if (<caret>test.Enum.A == test.Enum.A) 1 else 2)
+}