Consider cherry-pick of hpcng #6054 about singularity

[dtrudg]

Discussed with @tri-adam and did some trials - we don't appear to be affected by this due to disabling GC for the starter. The reproducer on the hpcng issue shows lsof output that includes the sandbox for CE 3.8.

Confirmed 3.7.4 does show the issue (lsof shows no sandbox)

11:15 AM $ singularity version 
3.7.4

11:15 AM $ ps aux | grep runtime
dtrudg     71249  4.8  0.2 1180260 22124 pts/0   Sl   11:15   0:00 Singularity runtime parent
dtrudg     71311  0.0  0.0 221400   856 pts/1    S+   11:15   0:00 grep --color=auto runtime

11:15 AM $ lsof -p 71249 | grep sandbox

CE 3.8.0 does not have the issue (lsof shows sandbox)

11:09 AM $ singularity version 
3.8.0+36-g9c3674c96

11:09 AM $ ps aux | grep runtime
dtrudg     39800  0.4  0.2 1179820 21988 pts/0   Sl   11:08   0:00 Singularity runtime parent
dtrudg     39912  0.0  0.0 221400   856 pts/1    S+   11:09   0:00 grep --color=auto runtime

11:09 AM $ lsof -p 39800 | grep sandbox
starter 39800 dtrudg    3r      DIR               0,49      560     163 /tmp/centos7-sandbox