Revert to the original code and exclude it unless objc runtime is available

Author: mtake

benchmark/single-source/MapReduce.swift

@@ -133,25 +133,29 @@ public func run_MapReduceShortString(_ N: Int) {
 
 @inline(never)
 public func run_MapReduceClass(_ N: Int) {
-  let numbers = (0..<1000).map { NSDecimalNumber(integerLiteral: $0) }
+#if _runtime(_ObjC)
+  let numbers = (0..<1000).map { NSDecimalNumber(value: $0) }
 
   var c = 0
   for _ in 1...N*100 {
     let mapped = numbers.map { $0.intValue &+ 5 }
     c += mapped.reduce(0, &+)
   }
   CheckResults(c != 0, "IncorrectResults in MapReduce")
+#endif
 }
 
 @inline(never)
 public func run_MapReduceClassShort(_ N: Int) {
-  let numbers = (0..<10).map { NSDecimalNumber(integerLiteral: $0) }
+#if _runtime(_ObjC)
+  let numbers = (0..<10).map { NSDecimalNumber(value: $0) }
 
   var c = 0
   for _ in 1...N*10000 {
     let mapped = numbers.map { $0.intValue &+ 5 }
     c += mapped.reduce(0, &+)
   }
   CheckResults(c != 0, "IncorrectResults in MapReduce")
+#endif
 }