test: subsys: cpp: Fix stack overflow on Armv8R-64

After doing some tests on Armv8R aarch64 board, the used stack memory
exceeds the stack size for about 64 bytes. Extending ZTEST_STACKSIZE
to 5120 can fix it.

Signed-off-by: Jaxson Han <jaxson.han@arm.com>
1 file changed