Add a fuzzer for the SSL_CTX API.

This is not a complete fuzzer, even for SSL_CTX, but it's a start.

Written in memory of c-ares[1].

[1] https://twitter.com/hanno/status/781506296906444800

Change-Id: I64b02c60f35b9057201df2cc325ebb7a84a0229d
Reviewed-on: https://boringssl-review.googlesource.com/11423
Reviewed-by: Adam Langley <alangley@gmail.com>
Commit-Queue: Adam Langley <alangley@gmail.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/FUZZING.md b/FUZZING.md
index c541a2d..1a21403 100644
--- a/FUZZING.md
+++ b/FUZZING.md
@@ -30,15 +30,16 @@
 
 The recommended values of `max_len` for each test are:
 
-| Test       | `max_len` value |
-|------------|-----------------|
-| `cert`     | 3072            |
-| `client`   | 20000           |
-| `pkcs8`    | 2048            |
-| `privkey`  | 2048            |
-| `server`   | 4096            |
-| `spki`     | 1024            |
-| `read_pem` | 512             |
+| Test          | `max_len` value |
+|---------------|-----------------|
+| `cert`        | 3072            |
+| `client`      | 20000           |
+| `pkcs8`       | 2048            |
+| `privkey`     | 2048            |
+| `server`      | 4096            |
+| `spki`        | 1024            |
+| `read_pem`    | 512             |
+| `ssl_ctx_api` | 256             |
 
 These were determined by rounding up the length of the largest case in the corpus.