This doesn't cover all the functions used by Node, but it's the easy
bits. (EVP_PKEY_paramgen will be done separately as its a non-trivial
bit of machinery.)

Change-Id: I6501e99f9239ffcdcc57b961ebe85d0ad3965549
Reviewed-on: https://boringssl-review.googlesource.com/c/34544
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>