LeakingThisInspection: fix false positives for enum class

#KT-25905 Fixed

idea/testData/inspectionsLocal/leakingThis/enumEntryHasOverriddenMember3.kt

@@ -0,0 +1,14 @@
+// PROBLEM: Calling non-final function toString in constructor
+// FIX: none
+enum class Fo(val b: Int) {
+    ONE(5) {
+        override val x = b
+        override fun toString(): String {
+            return x.toString()
+        }
+    };
+
+    abstract val x: Int
+
+    val dos = <caret>toString()
+}

idea/testData/inspectionsLocal/leakingThis/enumEntryHasOverriddenMember4.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+// FIX: none
+enum class Fo(val b: Int) {
+    ONE(5) {
+        override val x = b
+    };
+
+    abstract val x: Int
+
+    val dos = <caret>toString()
+}

idea/testData/inspectionsLocal/leakingThis/enumEntryHasOverriddenMember5.kt

@@ -0,0 +1,13 @@
+// PROBLEM: Accessing non-final property x in constructor
+// FIX: none
+enum class Foo : Bar {
+    ONE {
+        override val x = 1
+    };
+
+    val double = x<caret>
+}
+
+interface Bar {
+    val x: Int
+}

idea/testData/inspectionsLocal/leakingThis/enumEntryHasOverriddenMember6.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+// FIX: none
+enum class Foo : Bar {
+    ONE;
+
+    val double = x<caret>
+}
+
+interface Bar {
+    val x: Int get() = 42
+}

idea/testData/inspectionsLocal/leakingThis/enumEntryHasOverriddenMember7.kt

@@ -0,0 +1,14 @@
+// PROBLEM: none
+// FIX: none
+enum class Foo : Bar {
+    ONE {
+        override fun x() = 1
+    };
+
+    val double = <caret>x(2)
+}
+
+interface Bar {
+    fun x(): Int = 42
+    fun x(i: Int): Int = 24
+}