Make KotlinType.isError extension instead of member

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/internal/kotlinInternalUastUtils.kt

@@ -41,6 +41,7 @@ import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.types.isError
 import org.jetbrains.uast.*
 import java.lang.ref.WeakReference
 import java.text.StringCharacterIterator
@@ -172,4 +173,4 @@ internal inline fun <reified T : UDeclaration, reified P : PsiElement> unwrap(el
     val unwrapped = if (element is T) element.psi else element
     assert(unwrapped !is UElement)
     return unwrapped as P
-}
+}