[stdlib] Minor fixups for SE-0118 implementation

Author: Dave Abrahams

stdlib/private/StdlibUnittest/RaceTest.swift

@@ -47,7 +47,7 @@ import Glibc
 #if _runtime(_ObjC)
 import ObjectiveC
 #else
-func autoreleasepool(_ code: @noescape () -> Void) {
+func autoreleasepool(invoking code: @noescape () -> Void) {
   // Native runtime does not have autorelease pools.  Execute the code
   // directly.
   code()

stdlib/private/StdlibUnittestFoundationExtras/StdlibUnittestFoundationExtras.swift

@@ -68,7 +68,7 @@ public func autoreleasepoolIfUnoptimizedReturnAutoreleased(
   invoking body: @noescape () -> Void
 ) {
 #if arch(i386) && (os(iOS) || os(watchOS))
-  autoreleasepool(body)
+  autoreleasepool(invoking: body)
 #else
   body()
 #endif