selftests: defer: Allow spaces in arguments of deferred commands

Currently the way deferred commands are stored and invoked causes any
whitespace to act as an argument separator when the command is executed.
To make it possible to use spaces in deferred commands, store the commands
quoted, and then eval the string prior to execution.

Fixes: a6e263f ("selftests: net: lib: Introduce deferred commands")
Signed-off-by: Petr Machata <[email protected]>
Acked-by: Nikolay Aleksandrov <[email protected]>
Link: https://patch.msgid.link/6c2523139a6f99103889c9c9fedcdc66a75441f4.1757004393.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <[email protected]>

Author: pmachata

tools/testing/selftests/net/lib/sh/defer.sh

@@ -39,7 +39,7 @@ __defer__run()
 	local defer_ix=$1; shift
 	local defer_key=$(__defer__defer_key $track $defer_ix)
 
-	${__DEFER__JOBS[$defer_key]}
+	eval ${__DEFER__JOBS[$defer_key]}
 	unset __DEFER__JOBS[$defer_key]
 }
 
@@ -49,7 +49,7 @@ __defer__schedule()
 	local ndefers=$(__defer__ndefers $track)
 	local ndefers_key=$(__defer__ndefer_key $track)
 	local defer_key=$(__defer__defer_key $track $ndefers)
-	local defer="$@"
+	local defer="${@@Q}"
 
 	__DEFER__JOBS[$defer_key]="$defer"
 	__DEFER__NJOBS[$ndefers_key]=$((ndefers + 1))