Terminal: Use QtcProcess to start terminal window

Previously DesktopDevice::openTerminal used custom code to open a
terminal window. This patch changes it to use QtcProcess with
TerminalMode::On.

This also removes the need for "openTerminal.py" on macOS.

Change-Id: Iec978bdd19487ff8e59dcd88c35c2d01b0681022
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

src/libs/utils/terminalcommand.cpp

@@ -65,13 +65,7 @@ TerminalCommand TerminalCommand::defaultTerminalEmulator()
 
     if (defaultTerm.command.isEmpty()) {
         if (HostOsInfo::isMacHost()) {
-            const FilePath termCmd = FilePath::fromString(QCoreApplication::applicationDirPath())
-                            / "../Resources/scripts/openTerminal.py";
-            if (termCmd.exists())
-                defaultTerm = {termCmd, "", ""};
-            else
-                defaultTerm = {"/usr/X11/bin/xterm", "", "-e"};
-
+            return {"Terminal.app", "", ""};
         } else if (HostOsInfo::isAnyUnixHost()) {
             defaultTerm = {"xterm", "", "-e"};
             const Environment env = Environment::systemEnvironment();