Re: libstdc++/50862 fix deadlock in condition_variable_any

PR libstdc++/50862 * include/std/condition_variable (condition_variable_any::wait): Avoid terminating if relocking user mutex throws during stack-unwinding. * testsuite/30_threads/condition_variable_any/50862.cc: Add dg-require. Fixes two more issues pointed out in

libstdc++/50862 fix deadlock in condition_variable_any

PR libstdc++/50862 * include/std/condition_variable (condition_variable_any::wait): Fix deadlock and ensure _Lock::lock() is called on exit. (condition_variable_any::native_handle): Remove, as per LWG 1500. *