[lldb] Search both visionOS and XROS DeviceSupport directories (#228573)

Xcode now downloads visionOS shared cache symbols into
~/Library/Developer/Xcode/visionOS DeviceSupport, but
PlatformRemoteAppleXR only looked in "XROS DeviceSupport". As a result,
LLDB never found the expanded shared cache for visionOS devices and
failed to resolve symbols like `memcpy`, which breaks expression
evaluation and loading images into the inferior.

This makes `GetDeviceSupportDirectoryName` return a list of directory
names (renamed to `GetDeviceSupportDirectoryNames`) and have
`PlatformDarwinDevice` search each of them. visionOS returns both the
current and the legacy name; all other platforms keep their single name
for now.

rdar://189049149

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
GitOrigin-RevId: 6292b6e192d145579d80970260366ffb8489e107