Add inspection to move the variable declaration into when

#KT-29001 Fixed

idea/testData/inspectionsLocal/moveVariableDeclarationIntoWhen/notApplicableSideEffect.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+fun foo() {
+    val a<caret> = 1
+    val b = 42
+    when (a) {
+        1 -> {
+        }
+        else -> {
+        }
+    }
+}