Constructed types with a recursive definition could eventually exceed
the stack given malicious input with excessive recursion. Therefore we
limit the stack depth.

CVE-2018-0739

Credit to OSSFuzz for finding this issue.

(Imported from upstream's 9310d45087ae546e27e61ddf8f6367f29848220d.)

BoringSSL does not contain any such structures, but import this anyway
with a test.

Change-Id: I0e84578ea795134f25dae2ac8b565f3c26ef3204
Reviewed-on: https://boringssl-review.googlesource.com/26844
Commit-Queue: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>