Convert FoldInitializerAndIfToElvisIntention to inspection and decrease severity to INFO

#KT-19643 Fixed

idea/testData/inspectionsLocal/foldInitializerAndIfToElvis/ThrowInBlock.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+
+fun foo(p: List<String?>) {
+    val v = p[0]
+    <caret>if (v == null) {
+        throw RuntimeException()
+    }
+}