Change default of `DeserializationFeature.FAIL_ON_NULL_FOR_PRIMITIVES` to `true` for 3.0

[cowtowncoder]

Describe your Issue

As of Jackson 2.x, DeserializationFeature. FAIL_ON_NULL_FOR_PRIMITIVES defaults to false, allowing coercion from JSON null into Java int, long and so on.
For some users -- and especially on "low null" languages like Kotlin -- such coercion is rarely expected, so suggestion was made to change the default.

No decision is yet made: discussion for helping decision is here:

FasterXML/jackson-future-ideas#79

this issue is placeholder until decision is made.

[yawkat]

I assume title should say "change to true"?

Sounds like a good change to me.

[cowtowncoder]

@yawkat Thanks, yes fixed that typo. And looks like proposal is passing (5 to 1 voting as of now).

[cowtowncoder]

As per FasterXML/jackson-future-ideas#79, proposal approved, will work on this.

[JooHyukKim]

Added PR to push through changes in #4890.
Modified JSTEP-2 accordingly.