test: repair the Windows builders after swiftlang#32666

Adjust the test to fail properly

Author: compnerd

test/Prototypes/BigInt.swift

@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift -swift-version 4 -o %t/a.out %s
+// RUN: not --crash %target-build-swift -swift-version 4 -o %t/a.out %s
 // RUN: %target-run %t/a.out
 // REQUIRES: executable_test
 // REQUIRES: CPU=x86_64