Coq dev docker sometimes runs out of disk space

[JasonGross]

Following up on #2218, I see

Run echo "=== Disk space usage ==="
=== Disk space usage ===
Filesystem      Size  Used Avail Use% Mounted on
/dev/root        72G   65G  6.7G  91% /
tmpfs           7.9G   84K  7.9G   1% /dev/shm
tmpfs           3.2G  1.2M  3.2G   1% /run
tmpfs           5.0M     0  5.0M   0% /run/lock
/dev/sda16      881M   62M  758M   8% /boot
/dev/sda15      105M  6.2M   99M   6% /boot/efi
/dev/sdb1        74G  4.1G   66G   6% /mnt
tmpfs           1.6G   12K  1.6G   1% /run/user/1001

=== Top 20 largest directories in current directory ===
6.8G	.
5.3G	./src
4.2G	./src/ExtractionOCaml
662M	./src/ExtractionHaskell
228M	./src/ExtractionJsOfOCaml
140M	./rupicola
130M	./rupicola/bedrock2
98M	./src/Bedrock
56M	./src/Util
47M	./src/Assembly
45M	./dist
41M	./rewriter

Build cache usage: 39.92kB

CACHE ID       CACHE TYPE     SIZE      CREATED       LAST USED     USAGE     SHARED
llsdzsutyu9r   regular        0B        2 hours ago   2 hours ago   1         true
8sep3ifwjiyq   regular        0B        2 hours ago   2 hours ago   1         true
u4rw32qf8zt8   regular        0B        2 hours ago   2 hours ago   1         true
x587776g9wgk   regular        0B        2 hours ago   2 hours ago   1         true
td7co6pdwnla   regular        0B        2 hours ago   2 hours ago   1         true
gpu4ndid48ws   regular        0B        2 hours ago   2 hours ago   1         true
mqzegm7vlidi   regular        0B        2 hours ago   2 hours ago   1         true
y2avnno30s0w   regular        0B        2 hours ago   2 hours ago   1         true
kp6fssgtnpfo   regular        0B        2 hours ago   2 hours ago   1         true
hx3fsfuxlc7b   regular        0B        2 hours ago   2 hours ago   1         true
1ygurasojbxo   regular        0B        2 hours ago   2 hours ago   1         true
ff4fs2cwo3sb   regular        0B        2 hours ago   2 hours ago   1         true
wy2uf0i6t1y7   regular        0B        2 hours ago   2 hours ago   1         true
vcq9fhc18hrj   regular        0B        2 hours ago   2 hours ago   1         true
px1d8qhx2h20   regular        0B        2 hours ago   2 hours ago   1         true
iglt3amczgoj   regular        594B      2 hours ago   2 hours ago   1         true
vyvum0h6nflm   source.local   149B      2 hours ago   2 hours ago   1         false
b6xfqxy1vice   source.local   61B       2 hours ago   2 hours ago   1         false
3mofi0s2rdh3   regular        0B        2 hours ago   2 hours ago   1         true
9ib0zk05dj54   source.local   39.7kB    2 hours ago   2 hours ago   1         false
d88oudfn4rc4   regular        0B        2 hours ago   2 hours ago   1         true
pdsr9r7ah4dz   regular        29.1kB    2 hours ago   2 hours ago   1         true
uilhw6veymaf   regular        10kB      2 hours ago   2 hours ago   1         true
2s
58s
Run docker save "$COQ_IMAGE" -o image.tar
write ./.docker_temp_939995876: no space left on device
Error: Process completed with exit code 1.