tests: cmsis: Disable two cmsis portability tests on x86_64

These two tests are hitting a stack overflow on x86_64 (not entirely
surprisingly), but can't just increase stack size because there is an
assert in the CMSIS compatibility layer that stacks be under 512
bytes.  Just disable for now.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>

samples/portability/cmsis_rtos_v1/philosophers/sample.yaml

@@ -5,7 +5,7 @@ common:
   tags: cmsis_rtos_v1_philosopher
   min_ram: 32
   min_flash: 34
-  platform_exclude: qemu_xtensa
+  platform_exclude: qemu_xtensa qemu_x86_64
   harness: console
   harness_config:
     type: multi_line

tests/cmsis_rtos_v2/testcase.yaml

@@ -1,5 +1,6 @@
 tests:
   portability.cmsis_rtos_v2:
+    platform_exclude: qemu_x86_64
     tags: cmsis_rtos_v2
     min_ram: 32
     min_flash: 34