Revert "Fix SBDebugger::CreateTargetWithFileAndArch to accept LLDB_ARCH_DEFAULT."

Also revert "Follow on to: f05dc40c31d1883b46b8bb60547087db2f4c03e3"

After these changes, multiple lldb tests are failing. Calls to
CreateTargetWithFileAndArch(None, None) appear to fail after these
changes.

This reverts commit f05dc40c31d1883b46b8bb60547087db2f4c03e3 and
1fba21778f84f266f7d32153c88e59e1900fbe5b.

GitOrigin-RevId: 8b1171488575bd0b5ccb23bc1a3d22e2aaccb244
2 files changed