sanity: prevent stack corruption at test_static_idt

Stack for fiber idtSpurFiber at tests/legacy/kernel/test_static_idt
for nanokernel is not big enough since printk parse context refactor
(commit 3ab60466), causing sanity check to fail with CONFIG_DEBUG=y.

Change-Id: Iddc74a2800163a22be985067ce828ac859ae4a24
Signed-off-by: Genaro Saucedo Tejada <genaro.saucedo.tejada@intel.com>