tests: arch: arm_thread_swap: increase stack for no_optimizations

Under CONFIG_NO_OPTIMIZATIONS=y (-O0), the stack consumption for the
test threads in arm_thread_swap exceeds the default 1024-byte allocation
due to larger stack frames in unoptimized core kernel paths (such as
k_thread_priority_set, verify_callee_saved, and reschedule chains).
Because alt_thread_stack and user_thread_stack are sized with
1024 + CONFIG_TEST_EXTRA_STACK_SIZE, adjusting CONFIG_MAIN_STACK_SIZE
alone does not allocate extra space for these test threads.

Add CONFIG_TEST_EXTRA_STACK_SIZE=1024 to extra_configs in both
arch.arm.swap.common.no_optimizations and
arch.arm.swap.common.fpu_sharing.no_optimizations test scenarios to
provide sufficient stack budget under -O0.

Fixes #111477

Signed-off-by: harshit kudhial <harshitkudhial@gmail.com>

Author: harshitnub077

tests/arch/arm/arm_thread_swap/tests.yaml

@@ -15,6 +15,7 @@ tests:
       - CONFIG_ZTEST_WARN_NO_OPTIMIZATIONS=n
       - CONFIG_IDLE_STACK_SIZE=512
       - CONFIG_MAIN_STACK_SIZE=2048
+      - CONFIG_TEST_EXTRA_STACK_SIZE=1024
     min_flash: 192
   arch.arm.swap.common.fpu_sharing:
     filter: not CONFIG_TRUSTED_EXECUTION_NONSECURE and CONFIG_ARMV7_M_ARMV8_M_FP
@@ -30,4 +31,5 @@ tests:
       - CONFIG_ZTEST_WARN_NO_OPTIMIZATIONS=n
       - CONFIG_IDLE_STACK_SIZE=512
       - CONFIG_MAIN_STACK_SIZE=2048
+      - CONFIG_TEST_EXTRA_STACK_SIZE=1024
     min_flash: 192