Use the MAYBE/DISABLED pattern in RSATest.BlindingCacheConcurrency.

Change-Id: Ia3565c117eb952a106bc5f1ab7d5231708854483
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/39606
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/rsa_extra/rsa_test.cc b/crypto/rsa_extra/rsa_test.cc
index 0df21c0..76cf50a 100644
--- a/crypto/rsa_extra/rsa_test.cc
+++ b/crypto/rsa_extra/rsa_test.cc
@@ -1118,9 +1118,13 @@
   }
 }
 
-#if defined(OPENSSL_X86_64)
 // This test might be excessively slow on slower CPUs.
-TEST(RSATest, BlindingCacheConcurrency) {
+#if defined(OPENSSL_X86_64)
+#define MAYBE_BlindingCacheConcurrency BlindingCacheConcurrency
+#else
+#define MAYBE_BlindingCacheConcurrency DISABLED_BlindingCacheConcurrency
+#endif
+TEST(RSATest, MAYBE_BlindingCacheConcurrency) {
   bssl::UniquePtr<RSA> rsa(
       RSA_private_key_from_bytes(kKey1, sizeof(kKey1) - 1));
   ASSERT_TRUE(rsa);
@@ -1154,6 +1158,5 @@
     thread.join();
   }
 }
-#endif  // X86_64
 
 #endif  // THREADS