Fix deprecated Buffer constructor usage and add safeguards

[ChALkeR]

Two commits here, one for moving off the deprecated Buffer constructor API, and the second for the additional safeguards (just in case).

nodejsUtils: don't use deprecated Buffer api

This avoids using Buffer constructor API on newer Node.js versions.

To achieve that, Buffer.from presence is checked, with validating that it's
not the same method as Uint8Array.from.

Refs:
https://nodejs.org/api/deprecations.html#deprecations_dep0005_buffer_constructor

nodejsUtils: additional Buffer safeguards for older Node.js

1. In allocBuffer(), ensure buffers allocated with new Buffer() are zero-filled.
   On newer Node.js versions, Buffer.alloc() zero-fills already.

2. In newBufferFrom(), throw when 'data' argument is a number.
   On newer Node.js versions, Buffer.from(number)/new Buffer(number, encooding)
   throw already.

[ChALkeR]

Tracking: nodejs/node#19079

[arcanis]

Ping @dduponchel?

[zoe-mcelderry]

Is there any time line for addressing this issue please?