x86 architectures require a dynamic stack size that is a multiple
of 4096 bytes due to mmu restrictions.
For example, this test would previously fail when using the
default dynamic stack size of 1024 bytes for 32-bit
platforms.
```
west build -p auto -b qemu_x86/atom/nopae -t run \
tests/posix/common/ -- -DCONFIG_USERSPACE=y
```
It would pass with an additional argument
```
west build -p auto -b qemu_x86/atom/nopae -t run \
tests/posix/common/ -- -DCONFIG_USERSPACE=y \
-DCONFIG_DYNAMIC_THREAD_STACK_SIZE=4096
```
Add a special default for x86 when using dynamic thread stacks.
The x86 default removes the need for `boards/qemu_x86*.conf`,
with the exception of `qemu_x86_tiny`.
qemu_x86_tiny did not have sufficient memory (or configuration)
to run the non-userspace tests, so bump up the available ram
from 256k to 512k for this test and clone the .conf from the
demand paging tests.
Eventually, the common posix test should be split into more
concise functional categories.
Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>
b6aed5c505