tests: cpp: cxx: Add dynamic memory availability test for static init

This commit adds a test to verify that the dynamic memory allocation
service (the `new` operator) is available and functional when the C++
static global object constructors are invoked called during the system
initialisation.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
(cherry picked from commit dc4895b8)