[Bug testsuite/80221] Contrib script to rewrite testcase from absolute to relative line numbers

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80221
Bug 80221 depends on bug 80220, which changed state.

Bug 80220 Summary: relative line numbers don't work when put between braces
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80220

           What    |Removed                     |Added
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             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |WONTFIX