Pass --reuse-build only to commands that use DistUtilsCommandMixin

This is a concatenation of two upstream commits:
- https://code.qt.io/cgit/pyside/pyside-setup.git/commit/?id=ed0571df854a232e
- https://code.qt.io/cgit/pyside/pyside-setup.git/commit/?id=3f00c2adad2e38b0

Gbp-Pq: Name fix-reuse-build.patch

Blacklist failing tests

Forwarded:
https://bugreports.qt.io/projects/PYSIDE/issues/PYSIDE-1146?filter=allopenissues

Gbp-Pq: Name blacklist-failing-tests.patch

Fix spelling errors

Last-Update: 2018-07-12

Gbp-Pq: Name fix-spelling-errors.patch

Update import of PyQt5 private sip module and remove Python 2/PyQt4 setapi calls

Last-Updated: 2020-12-20

Gbp-Pq: Name update-sip-import.patch

pyside2 (5.15.2-1) unstable; urgency=medium

  * Team upload.
  * Add missing dependencies to make the autopkgtest pass again.
  * Backport proposed upstream patch to fix qApp flags handling.
    - Unblacklist QtWidgets::bug_307 test, it should not fail anymore.

[dgit import unpatched pyside2 5.15.2-1]

Import pyside2_5.15.2-1.debian.tar.xz

[dgit import tarball pyside2 5.15.2-1 pyside2_5.15.2-1.debian.tar.xz]

Import pyside2_5.15.2.orig.tar.gz

[dgit import orig pyside2_5.15.2.orig.tar.gz]