tests/histedit-helpers.sh

requirements: introduce constants for `shared` and `relshared` requirements

We add them to `WORKING_DIR_REQUIREMENTS` too as they should be stored in
`.hg/requires` and have information about the type of working copy.

Differential Revision: https://phab.mercurial-scm.org/D8926

fixbundle() {
    grep -v 'saving bundle' | grep -v 'saved backup' | \
        grep -v added | grep -v adding | \
        grep -v "unable to find 'e' for patching" | \
        grep -v "e: No such file or directory" | \
    cat
}