Make sure servers get killed on user-initiated quit. If we just HUP the shell...

Make sure servers get killed on user-initiated quit. If we just HUP the shell then the server won't notice until it becomes attached as an orphan on the next launch. Issue 6369

sources/PTYSession.m

@@ -1794,7 +1794,7 @@ ITERM_WEAKLY_REFERENCEABLE
         [self replaceTerminatedShellWithNewInstance];
     } else {
         _shouldRestart = YES;
-        [_shell sendSignal:SIGKILL];
+        [_shell sendSignal:SIGKILL toServer:NO];
     }
 }

sources/PTYTask.h

@@ -70,7 +70,7 @@ extern NSString *kCoprocessStatusChangeNotification;
 - (void)writeTask:(NSData*)data;
-- (void)sendSignal:(int)signo;
+- (void)sendSignal:(int)signo toServer:(BOOL)toServer;
 // Cause the slave to receive a SIGWINCH and change the tty's window size. If `size` equals the
 // tty's current window size then no action is taken.

sources/PTYTask.m

@@ -828,8 +828,11 @@ static int MyForkPty(int *amaster,
     [self.delegate threadedTaskBrokenPipe];
 }
-- (void)sendSignal:(int)signo {
-    if (_serverChildPid != -1) {
+- (void)sendSignal:(int)signo toServer:(BOOL)toServer {
+    if (toServer && _serverPid != -1) {
+        DLog(@"Sending signal to server %@", @(_serverPid));
+        kill(_serverPid, signo);
+    } else if (_serverChildPid != -1) {
         kill(_serverChildPid, signo);
      } else if (_childPid >= 0) {
          kill(_childPid, signo);
@@ -931,7 +934,7 @@ static int MyForkPty(int *amaster,
 - (void)stop {
     self.paused = NO;
     [self stopLogging];
-    [self sendSignal:SIGHUP];
+    [self sendSignal:SIGHUP toServer:NO];
     [self killServerIfRunning];
     if (fd >= 0) {

sources/iTermController.m

@@ -1370,7 +1370,10 @@ static iTermController *gSharedInstance;
     assert([iTermAdvancedSettingsModel runJobsInServers]);
     for (iTermRestorableSession *restorableSession in _restorableSessions) {
         for (PTYSession *aSession in restorableSession.sessions) {
-            [aSession.shell sendSignal:SIGHUP];
+            if (aSession.shell.serverPid != -1) {
+                [aSession.shell sendSignal:SIGKILL toServer:YES];
+            }
+            [aSession.shell sendSignal:SIGHUP toServer:YES];
         }
     }
 }