scons: add missing checkTarget in setup hook

The checkTarget variable is explicitly tested before, but not passed to
scons.

This was apparently missed in the initial commit for that setupHook in
#50293.

pkgs/by-name/sc/scons/setup-hook.sh

@@ -61,7 +61,7 @@ sconsCheckPhase() {
  local flagsArray=(
  ${enableParallelChecking:+-j${NIX_BUILD_CORES}}
  )
- concatTo flagsArray sconsFlags sconsFlagsArray checkFlagsArray
+ concatTo flagsArray sconsFlags sconsFlagsArray checkFlagsArray checkTarget
 
  echoCmd 'scons check flags' "${flagsArray[@]}"
  scons "${flagsArray[@]}"