use -r:off for runnableExamples that should compile but not run (#17203)

* use -r:off for runnableExamples that should compile but not run

* use -r:off in other RT disabled tests

lib/pure/asynchttpserver.nim

@@ -14,32 +14,30 @@
 ## application in production you should use a reverse proxy (for example nginx)
 ## instead of allowing users to connect directly to this server.
 
-runnableExamples:
+runnableExamples("-r:off"):
   # This example will create an HTTP server on port 8080. The server will
   # respond to all requests with a `200 OK` response code and "Hello World"
-  # as the response body. Run locally with:
-  # `nim doc --doccmd:-d:nimAsyncHttpServerEnableTest --lib:lib lib/pure/asynchttpserver.nim`
+  # as the response body.
   import std/asyncdispatch
-  if defined(nimAsyncHttpServerEnableTest):
-    proc main {.async.} =
-      const port = 8080
-      var server = newAsyncHttpServer()
-      proc cb(req: Request) {.async.} =
-        echo (req.reqMethod, req.url, req.headers)
-        let headers = {"Content-type": "text/plain; charset=utf-8"}
-        await req.respond(Http200, "Hello World", headers.newHttpHeaders())
+  proc main {.async.} =
+    const port = 8080
+    var server = newAsyncHttpServer()
+    proc cb(req: Request) {.async.} =
+      echo (req.reqMethod, req.url, req.headers)
+      let headers = {"Content-type": "text/plain; charset=utf-8"}
+      await req.respond(Http200, "Hello World", headers.newHttpHeaders())
 
-      echo "test this with: curl localhost:" & $port & "/"
-      server.listen(Port(port))
-      while true:
-        if server.shouldAcceptRequest():
-          await server.acceptRequest(cb)
-        else:
-          # too many concurrent connections, `maxFDs` exceeded
-          # wait 500ms for FDs to be closed
-          await sleepAsync(500)
+    echo "test this with: curl localhost:" & $port & "/"
+    server.listen(Port(port))
+    while true:
+      if server.shouldAcceptRequest():
+        await server.acceptRequest(cb)
+      else:
+        # too many concurrent connections, `maxFDs` exceeded
+        # wait 500ms for FDs to be closed
+        await sleepAsync(500)
 
-    waitFor main()
+  waitFor main()
 
 import asyncnet, asyncdispatch, parseutils, uri, strutils
 import httpcore