Fix REQUIRES: line in 26725-llvm-smallvectorimpl-swift-diagnosticargument-operator.swift, it was never being run

Author: slavapestov

validation-test/compiler_crashers_fixed/26725-llvm-smallvectorimpl-swift-diagnosticargument-operator.swift

@@ -6,6 +6,5 @@
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
 // RUN: not %target-swift-frontend %s -typecheck
-// This test fails in the AST verifier, which can be turned off.
-// REQUIRES: swift_ast_verifier
+// REQUIRES: asserts
 class a<T where g:d{class A{class A<T>:A{init(){T{