"Cascade if" inspection: don't highlight for complex logical conditions

Related to KT-18615

idea/testData/inspectionsLocal/cascadeIf/complex.kt

@@ -0,0 +1,16 @@
+// PROBLEM: none
+
+fun foo(a: Boolean, b: Boolean, c: Boolean) {
+    <caret>if (a) {
+
+    }
+    else if (b && c) {
+
+    }
+    else if (!c) {
+
+    }
+    else {
+
+    }
+}