gitlab: disable debug info on CI builds

gitlab: disable debug info on CI builds

Our default build enables debug info which adds hugely to the size of
the builds as well as the size of cached objects. Disable debug info
across the board to save space and reduce pressure on the CI system.
We still have a number of builds which explicitly enable debug and
related extra asserts like --enable-debug-tcg.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-ID: <20250603110204.838117-3-alex.bennee@linaro.org>