"Replace 'when' with 'if'" intention: do not suggest if 'when' subject is variable declaration

#KT-35528 Fixed

idea/testData/intentions/branched/ifWhen/whenToIf/variableSubject.kt

@@ -0,0 +1,13 @@
+// IS_APPLICABLE: false
+enum class Type {
+    HYDRO,
+    PYRO
+}
+
+fun select(t: Type): Int {
+    return <caret>when (val i = t.ordinal) {
+        0 -> 1
+        1 -> 42
+        else -> i
+    }
+}