The shutdown system test is not capturing enough

Job #1631511 failed for 0a08de65:

The shutdown system test in rndc mode is just asserting without leaving enough forensic evidence to continue. named.run ends with the following which could indicate that named is deadlocked but without a core we can't know.

12-Apr-2021 02:03:53.895 fctx 0x7b6800240000(uoilpwjnw.test/A): doshutdown
12-Apr-2021 02:03:53.895 fctx 0x7b6800240000(uoilpwjnw.test/A): stopqueries
12-Apr-2021 02:03:53.895 fctx 0x7b6800240000(uoilpwjnw.test/A): cancelqueries
12-Apr-2021 02:03:53.895 dns_adb_destroyfind on find 0x7b4000058c00
12-Apr-2021 02:03:53.895 fctx 0x7b6800240000(uoilpwjnw.test/A): unlink
12-Apr-2021 02:03:53.895 fctx 0x7b6800240000(uoilpwjnw.test/A): destroy
12-Apr-2021 02:03:53.907 allocate new control connection
12-Apr-2021 02:03:53.907 allocate new control connection
12-Apr-2021 02:03:53.907 received control channel command 'status'
12-Apr-2021 02:03:53.907 received control channel command 'status'
12-Apr-2021 02:03:53.907 freeing control connection
12-Apr-2021 02:03:53.907 freeing control connection
12-Apr-2021 02:03:53.911 allocate new control connection
12-Apr-2021 02:03:53.911 received control channel command 'status'
12-Apr-2021 02:03:53.911 freeing control connection