Rename and deprecate ad-hoc IsNullOrEmpty.

idea/src/org/jetbrains/kotlin/idea/completion/smart/StaticMembers.kt

@@ -122,7 +122,7 @@ class StaticMembers(
                     presentation.setTailText(tailText, true)
                 }
 
-                if (presentation.getTypeText().isNullOrEmpty()) {
+                if (presentation.getTypeText().isNullOrEmptyDeprecated()) {
                     presentation.setTypeText(DescriptorRenderer.SHORT_NAMES_IN_TYPES.renderType(classDescriptor.getDefaultType()))
                 }
             }

idea/src/org/jetbrains/kotlin/idea/completion/smart/Utils.kt

@@ -261,7 +261,8 @@ fun LookupElementFactory.createLookupElement(
 fun <T : Any> T?.toList(): List<T> = if (this != null) listOf(this) else listOf()
 fun <T : Any> T?.toSet(): Set<T> = if (this != null) setOf(this) else setOf()
 
-fun String?.isNullOrEmpty() = this == null || this.isEmpty()
+deprecated("Use String?.isNullOrEmpty() from stdlib when available")
+fun String?.isNullOrEmptyDeprecated() = this == null || this.isEmpty()
 
 enum class SmartCompletionItemPriority {
     IT