fix: add support for hard shutdown on SIGKILL (remy#1720)

This commit adds back the hard shutdown behaviour under Windows
as an opt-in: If the --signal option is "SIGKILL" nodemon will
terminate the process group by force without waiting for the
process to clean-up. This matches a SIGKILL on a UNIX system.

lib/monitor/run.js

@@ -313,6 +313,22 @@ function kill(child, signal, callback) {
 
   if (utils.isWindows) {
 
+    // We are handling a 'SIGKILL' POSIX signal under Windows the
+    // same way it is handled on a UNIX system: We are performing
+    // a hard shutdown without waiting for the process to clean-up.
+    if (signal === 'SIGKILL') {
+
+      debug('terminating process group by force: %s', child.pid);
+
+      // We are using the taskkill utility to terminate the whole
+      // process group ('/t') of the child ('/pid') by force ('/f').
+      // We need to end all sub processes, because the 'child'
+      // process in this context is actually a cmd.exe wrapper.
+      exec(`taskkill /f /t /pid ${child.pid}`);
+      callback();
+      return;
+    }
+
     // We are using the Windows Management Instrumentation Command-line
     // (wmic.exe) to resolve the sub-child process identifier, because the
     // 'child' process in this context is actually a cmd.exe wrapper.