MB-9482 Add support for V8 versions post 3.19

v8 versions post v3.19 does not allow copyable persistent objects
and few APIs have changed. Based on macro def `V8_POST_3_19_API`,
newer API or older API can be conditionally used.

Change-Id: I2e41b7274745289ee6b4c94b5c3ae7ea94da4a76
Reviewed-on: http://review.couchbase.org/37507
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Sarath Lakshman <sarath@couchbase.com>
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>