Bug#708060: debcheck: :$arch and :native always appear broken

["Rebecca N. Palmer" <rebecca_palmer@zoho.com>]

Control: retitle -1 debcheck: :$arch and :native always appear broken

Since 
https://salsa.debian.org/qa/qa/-/commit/526d2319174cb15111bb2d6c702f8e23ee7bd0d7 
, arch-specific Depends don't crash debcheck, but do search for a 
package named literally $package:$arch not just $package.  As this does 
not exist, they hence always appear broken.  (E.g. 
https://qa.debian.org/debcheck.php?dist=sid&package=wine wine64-tools.)

:any and :native Build-Depends have the same problem.  (:any Depends are 
treated as plain Depends, by an explicit substitution at line 385.)

A potential fix is to extract the arch qualifier as a separate regex 
group, as is already done for the version.