Add a check for `size < 0` to `assertSize()`, as passing a negative
value almost certainly indicates a programming error.
This also lines up the behaviour of `.allocUnsafe()` with the ones
of `.alloc()` and `.allocUnsafeSlow()` (which previously threw errors
from the Uint8Array constructor).
Notably, this also affects `Buffer()` calls with negative arguments.
PR-URL: #7079
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yorkie Liu <yorkiefixer@gmail.com>

Notable Changes:
* Buffer
  * Passing invalid input to Buffer.byteLength will now throw an error [#8946](#8946).
  * Calling Buffer without new is now deprecated and will emit a process warning [#8169](#8169).
  * Passing a negative number to allocUnsafe will now throw an error [#7079](#7079).
* Child Process
  * The fork and execFile methods now have stronger argument validation [#7399](#7399).
* Cluster
  * The worker.suicide method is deprecated and will emit a process warning [#3747](#3747).
* Deps
  * V8 has been updated to 5.4.500.36 [#8317](#8317), [#8852](#8852), [#9253](#9253).
  * NODE_MODULE_VERSION has been updated to 51 [#8808](#8808).
* File System
  * A process warning is emitted if a callback is not passed to async file system methods [#7897](#7897).
* Intl
  * Intl.v8BreakIterator constructor has been deprecated and will emit a process warning [#8908](#8908).
* Promises
  * Unhandled Promise rejections have been deprecated and will emit a process warning [#8217](#8217).
* Punycode
  * The `punycode` module has been deprecated [#7941](#7941).
* URL
  * An Experimental WHATWG URL Parser has been introduced [#7448](#7448).
PR-URL: #9099

Notable Changes:
* Buffer
  * Passing invalid input to Buffer.byteLength will now throw an error [#8946](#8946).
  * Calling Buffer without new is now deprecated and will emit a process warning [#8169](#8169).
  * Passing a negative number to allocUnsafe will now throw an error [#7079](#7079).
* Child Process
  * The fork and execFile methods now have stronger argument validation [#7399](#7399).
* Cluster
  * The worker.suicide method is deprecated and will emit a process warning [#3747](#3747).
* Deps
  * V8 has been updated to 5.4.500.36 [#8317](#8317), [#8852](#8852), [#9253](#9253).
  * NODE_MODULE_VERSION has been updated to 51 [#8808](#8808).
* File System
  * A process warning is emitted if a callback is not passed to async file system methods [#7897](#7897).
* Intl
  * Intl.v8BreakIterator constructor has been deprecated and will emit a process warning [#8908](#8908).
* Promises
  * Unhandled Promise rejections have been deprecated and will emit a process warning [#8217](#8217).
* Punycode
  * The `punycode` module has been deprecated [#7941](#7941).
* URL
  * An Experimental WHATWG URL Parser has been introduced [#7448](#7448).
PR-URL: #9099

    Notable Changes:
    * Buffer
      * Passing invalid input to Buffer.byteLength will now throw an error [#8946](nodejs/node#8946).
      * Calling Buffer without new is now deprecated and will emit a process warning [#8169](nodejs/node#8169).
      * Passing a negative number to allocUnsafe will now throw an error [#7079](nodejs/node#7079).
    * Child Process
      * The fork and execFile methods now have stronger argument validation [#7399](nodejs/node#7399).
    * Cluster
      * The worker.suicide method is deprecated and will emit a process warning [#3747](nodejs/node#3747).
    * Deps
      * V8 has been updated to 5.4.500.36 [#8317](nodejs/node#8317), [#8852](nodejs/node#8852), [#9253](nodejs/node#9253).
      * NODE_MODULE_VERSION has been updated to 51 [#8808](nodejs/node#8808).
    * File System
      * A process warning is emitted if a callback is not passed to async file system methods [#7897](nodejs/node#7897).
    * Intl
      * Intl.v8BreakIterator constructor has been deprecated and will emit a process warning [#8908](nodejs/node#8908).
    * Promises
      * Unhandled Promise rejections have been deprecated and will emit a process warning [#8217](nodejs/node#8217).
    * Punycode
      * The `punycode` module has been deprecated [#7941](nodejs/node#7941).
    * URL
      * An Experimental WHATWG URL Parser has been introduced [#7448](nodejs/node#7448).
Signed-off-by: Ilkka Myller <ilkka.myller@nodefield.com>