JSON fixes cause SV leakage between threads
Since recently we see this during os-autoinst shutdown:
Scalars leaked: -1
done joining commands thread
Attempt to free unreferenced scalar: SV 0x673ca28, Perl interpreter: 0x274b010 during global destruction.
Scalars leaked: 1
I bisected and can safely blame https://github.com/os-autoinst/os-autoinst/commit/065499506254aa50c349d4361699534dd43c199e now