tests: don't hardcode /bin/kill in the kill tests

If the 'kill' test is executed with --use-system-commands, it calls
/bin/kill to avoid the shell's own kill command being invoked.

However, this doesn't work if the kill we want to test isn't in fact in
/bin.  Instead, use $(which kill) to find a kill on the PATH and call
that directly.

Signed-off-by: Ross Burton <ross.burton@arm.com>

tests/ts/kill/all_processes

@@ -22,7 +22,7 @@ ts_skip_nonroot
 
 # make sure we do not use shell built-in command
 if [ "$TS_USE_SYSTEM_COMMANDS" == "yes" ]; then
-	TS_CMD_KILL="/bin/kill"
+	TS_CMD_KILL="$(which kill)"
 fi
 
 ts_check_test_command "$TS_CMD_KILL"

tests/ts/kill/name_to_number

@@ -20,7 +20,7 @@ ts_init "$*"
 
 # make sure we do not use shell built-in command
 if [ "$TS_USE_SYSTEM_COMMANDS" == "yes" ]; then
-	TS_CMD_KILL="/bin/kill"
+	TS_CMD_KILL="$(which kill)"
 fi
 
 ts_check_test_command "$TS_CMD_KILL"

tests/ts/kill/options

@@ -20,7 +20,7 @@ ts_init "$*"
 
 # make sure we do not use shell built-in command
 if [ "$TS_USE_SYSTEM_COMMANDS" == "yes" ]; then
-	TS_CMD_KILL="/bin/kill"
+	TS_CMD_KILL="$(which kill)"
 fi
 
 ts_check_test_command "$TS_CMD_KILL"

tests/ts/kill/print_pid

@@ -20,7 +20,7 @@ ts_init "$*"
 
 # make sure we do not use shell built-in command
 if [ "$TS_USE_SYSTEM_COMMANDS" == "yes" ]; then
-	TS_CMD_KILL="/bin/kill"
+	TS_CMD_KILL="$(which kill)"
 fi
 
 ts_check_test_command "$TS_CMD_KILL"

tests/ts/kill/queue

@@ -20,7 +20,7 @@ ts_init "$*"
 
 # make sure we do not use shell built-in command
 if [ "$TS_USE_SYSTEM_COMMANDS" == "yes" ]; then
-	TS_CMD_KILL="/bin/kill"
+	TS_CMD_KILL="$(which kill)"
 fi
 
 ts_check_test_command "$TS_CMD_KILL"