Notable changes:

* build:
  - Add support for Intel's VTune JIT profiling when compiled with
    --enable-vtune-profiling. For more information about VTune, see
    https://software.intel.com/en-us/node/544211. (Chunyang Dai) #3785.
  - Properly enable V8 snapshots by default. Due to a configuration
    error, snapshots have been kept off by default when the intention
    is for the feature to be enabled. (Fedor Indutny) #3962.
* crypto:
  - Simplify use of ECDH (Elliptic Curve Diffie-Hellman) objects
    (created via crypto.createECDH(curve_name)) with private keys that
    are not dynamically generated via generateKeys(). The public key
    is now computed when explicitly setting a private key. Added
    validity checks to reduce the possibility of computing weak or
    invalid shared secrets. Also, deprecated the setPublicKey() method
    for ECDH objects as its usage is unnecessary and can lead to
    inconsistent state. (Michael Ruddy) #3511.
  - Update root certificates from the current list stored maintained
    by Mozilla NSS. (Ben Noordhuis) #3951.
  - Multiple CA certificates can now be passed with the ca option to
    TLS methods as an array of strings or in a single new-line
    separated string. (Ben Noordhuis) #4099
* tools: Include a tick processor in core, exposed via the
  --prof-process command-line argument which can be used to process V8
  profiling output files generated when using the --prof command-line
  argument. (Matt Loring) #4021.

PR-URL: #4181