kernel32: Rewrote the locale matching to match more elements and to support Windows-format locale names.

Added implementation for LocaleNameToLCID and LCIDToLocaleName.

This reverts commit 9e772d13.

rpcrt4: Use SecInvalidateHandle and SecIsValidHandle for handling RpcConnection::ctx instead of setting/comparing the field to 0.

RPCRT4_CreateConnection fails by checking the return value from the
function and returning in this case.

(spotted by Peter Oberndorfer).