Array: Initialisation of internal variables

[adbridge]

The following internals should be initialised to sensible defaults (in most cases 0) in the constructor.

_grow_capacity _alloc_traits _alignment _capacity _elements

[bogdanm]

The thing to decide here is if we keep the current double step initialization (constructor+init()) of all the containers in core-util. If we do (which I think is a good idea) we'll have to guard against cases when the user didn't call init before attempting an array operation.

[ciarmcom]

ARM Internal Ref: IOTSFW-2002

[0xc0170]

73 fixes this, class member initializers were added