NSS: reject DH groups smaller than 1024 bits.

Since some platforms are still using NSS for now, this change mirrors https://boringssl-review.googlesource.com/#/c/4813/ in NSS.

BUG=490240

Review URL: https://codereview.chromium.org/1143303002

Cr-Commit-Position: refs/heads/master@{#330791}
4 files changed