Set the fuzzer PBKDF2 limit to 2048.

Our test data uses values to up 2048 so the 1024 limit was causing tests
to fail in fuzzing mode.

Change-Id: I71b97be26376a04c13d1f438e5e36a5ffff1c1a4
Reviewed-on: https://boringssl-review.googlesource.com/30484
Commit-Queue: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

crypto/pkcs8/pkcs8_x509.c

diff --git a/crypto/pkcs8/pkcs8_x509.c b/crypto/pkcs8/pkcs8_x509.c
index 6538963..c5a0651 100644
--- a/crypto/pkcs8/pkcs8_x509.c
+++ b/crypto/pkcs8/pkcs8_x509.c
@@ -670,7 +670,7 @@
     }
 
 #if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
-    static const uint64_t kIterationsLimit = 1024;
+    static const uint64_t kIterationsLimit = 2048;
 #else
     // Windows imposes a limit of 600K. Mozilla say: “so them increasing
     // maximum to something like 100M or 1G (to have few decades of breathing