Fix 2 tests on FreeBSD by initializing freebsd_environ

[yurivict]

No description provided.

[jenkins-cscs]

Can one of the admins verify this patch?

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ +0.12%	✅ ∅

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (3521f71)	222028	188803	85.04%
Head commit (d3bb5b1)	191067 (-30961)	162704 (-26099)	85.16% (+0.12%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#6503)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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[hkaiser]

LGTM, thanks!

[hkaiser]

Congratulations, your first PR to the HPX repository has just been merged! As a 'thank you' we offer a free STE||AR-Group t-shirt to all of our first-time contributors. If you are interested in receiving one, please get back to me directly so we can set up the delivery.