Prevent the background test components from waiting forever for the following PV process to start.

tests/Integrity_-_When_adjusted_remotely.test

@@ -28,7 +28,7 @@ true > "${workFile4}"
 (
 set +e
 # Don't start doing anything until the main transfer process, started below, has begun.
-while ! test -s "${workFile4}"; do sleep 0.1; done
+while test -e "${workFile4}" && ! test -s "${workFile4}"; do sleep 0.1; done
 sleep 2
 for loopCount in 1 2 3; do
 	"${testSubject}" -R "$(cat "${workFile4}")" -apterb	|| exit 1

tests/Memory_safety_-_Remote_control_receiver.test

@@ -27,7 +27,7 @@ dd if=/dev/urandom of="${workFile1}" bs=1024 count=10240 2>/dev/null
 true > "${workFile3}"
 (
 set +e
-while ! test -s "${workFile3}"; do usleep 200000 2>/dev/null || sleep 1; done
+while test -e "${workFile3}" && ! test -s "${workFile3}"; do usleep 200000 2>/dev/null || sleep 1; done
 for loopCount in 1 2 3; do
 	"${testSubject}" -R "$(cat "${workFile3}")" -apterb	|| exit 1
 	(usleep 200000 || sleep 1) 2>/dev/null

tests/Memory_safety_-_Remote_control_sender.test

@@ -27,7 +27,7 @@ dd if=/dev/urandom of="${workFile1}" bs=1024 count=10240 2>/dev/null
 # Check from the POV of the process sending a control command.
 true > "${workFile3}"
 "${testSubject}" -L 100k -i 0.1 -f -P "${workFile3}" "${workFile1}" > "${workFile2}" 2>/dev/null &
-while ! test -s "${workFile3}"; do usleep 200000 2>/dev/null || sleep 1; done
+while test -e "${workFile3}" && ! test -s "${workFile3}"; do usleep 200000 2>/dev/null || sleep 1; done
 runWithValgrind -R "$(cat "${workFile3}")" -apterb 4>&1   || exit 1
 (usleep 200000 || sleep 1) 2>/dev/null
 runWithValgrind -R "$(cat "${workFile3}")" -p 4>&1        || exit 1

tests/Memory_safety_-_Watchfd.test

@@ -37,7 +37,7 @@ fi
 seq 1 100 > "${workFile1}"
 true > "${workFile3}"
 # shellcheck disable=SC2030
-(while ! test -s "${workFile3}"; do sleep 0.1; done; sleep 1; read -r line; sleep 1; read -r line; sleep 1) <"${workFile1}" &
+(while test -e "${workFile3}" && ! test -s "${workFile3}"; do sleep 0.1; done; sleep 1; read -r line; sleep 1; read -r line; sleep 1) <"${workFile1}" &
 pid=$!
 sleep 0.1
 { runWithValgrind -P "${workFile3}" -d "${pid}:0" -f -i 0.5 >/dev/null 2>&1; } 4>&1 || exit 1
@@ -48,7 +48,7 @@ seq 1 300 > "${workFile2}"
 true > "${workFile3}"
 # shellcheck disable=SC2030
 (
-while ! test -s "${workFile3}"; do sleep 0.1; done
+while test -e "${workFile3}" && ! test -s "${workFile3}"; do sleep 0.1; done
 sleep 1
 read -r line
 exec 9<"${workFile2}"

tests/Transfer_-_--remote.test

@@ -23,7 +23,7 @@ dd if=/dev/zero of="${workFile1}" bs=1024 count=10240 2>/dev/null
 true > "${workFile4}"
 (
 # Don't start doing anything until the main transfer process, started below, has begun.
-while ! test -s "${workFile4}"; do sleep 0.1; done
+while test -e "${workFile4}" && ! test -s "${workFile4}"; do sleep 0.1; done
 sleep 1
 "${testSubject}" -R "$(cat "${workFile4}")" -a
 sleep 2

tests/Watchfd_-_Multiple_descriptors.test

@@ -27,7 +27,7 @@ seq 1 300 > "${workFile2}"
 # NB we just export line to make shellcheck think it's used.
 true > "${workFile3}"
 (
-while ! test -s "${workFile3}"; do sleep 0.1; done
+while test -e "${workFile3}" && ! test -s "${workFile3}"; do sleep 0.1; done
 export line
 sleep 1
 read -r line

tests/Watchfd_-_Single_descriptor.test

@@ -24,7 +24,7 @@ seq 1 100 > "${workFile1}"
 # NB we just export line to make shellcheck think it's used.
 true > "${workFile3}"
 (
-while ! test -s "${workFile3}"; do sleep 0.1; done
+while test -e "${workFile3}" && ! test -s "${workFile3}"; do sleep 0.1; done
 export line; sleep 1; read -r line; sleep 1; read -r line; sleep 1
 ) <"${workFile1}" &
 pid=$!