Oracle Linux 8 shell doesn't always restore environment variable correctly

Job #3374668 failed for 0592aaa4:

I saw that dig was making AAAA queries instead of A queries by default a couple of times developing !7888 (merged). Earlier in the resolver test we use HOME="$(pwd)" dig_with_opts @10.53.0.4 . > dig.out.1.${n} || ret=1 a few times. This shouldn't have a long term effect on HOME but that is the only explanation that makes sense. Creating an explicit sub shell should fix the issue. For !7888 (merged) I explicitly set the type.

Note below the type was not specified but should default to A.

% more dig.out.60 

; <<>> DiG 9.19.14-dev <<>> -p 14345 +tcp @10.53.0.5 options-formerr
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54036
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: 31786a72177b15f101000000645c36ee6cd499386040212e (good)
;; QUESTION SECTION:
;options-formerr.               IN      AAAA

;; AUTHORITY SECTION:
options-formerr.        1       IN      SOA     . . 0 0 0 0 0

;; Query time: 0 msec
;; SERVER: 10.53.0.5#14345(10.53.0.5) (TCP)
;; WHEN: Thu May 11 00:29:34 UTC 2023
;; MSG SIZE  rcvd: 106

%