Fix Qt's rcc determinism for depends/gitian

Summary:
Backport of https://bugreports.qt.io/browse/QTBUG-62511 to resolve
locale determinism during the build process.

This is a backport of Core's PR13732

Depends on D1821

Test Plan:

make -C ../depends build-all

Reviewers: #bitcoin_abc, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D1822