Kotlin: Remove cast from extractRawMethodAccess

I'm not entirely happy with this, but it at least meets the goal of
removing the cast.

Author: igfoo

java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt

@@ -1427,12 +1427,14 @@ open class KotlinFileExtractor(
         // type arguments at index -2, -3, ...
         extractTypeArguments(typeArguments, locId, id, enclosingCallable, enclosingStmt, -2, true)
 
-        val isFunctionInvoke =
-                   drType is IrSimpleType
-                && drType.isFunctionOrKFunction()
-                && callTarget.name.asString() == OperatorNameConventions.INVOKE.asString()
-        val isBigArityFunctionInvoke = isFunctionInvoke
-                && (drType as IrSimpleType).arguments.size > BuiltInFunctionArity.BIG_ARITY
+        val (isFunctionInvoke, isBigArityFunctionInvoke) =
+                if (drType is IrSimpleType &&
+                    drType.isFunctionOrKFunction() &&
+                    callTarget.name.asString() == OperatorNameConventions.INVOKE.asString()) {
+                    Pair(true, drType.arguments.size > BuiltInFunctionArity.BIG_ARITY)
+                } else {
+                    Pair(false, false)
+                }
 
         if (callTarget.isLocalFunction()) {
             val ids = getLocallyVisibleFunctionLabels(callTarget)