net/http: revert fix request canceler leak on connection close

This reverts commit 291a32a
due to flaking test.

Updates golang#61708

Author: AlexanderYastrebov

src/net/http/transport.go

@@ -2267,7 +2267,6 @@ func (pc *persistConn) readLoop() {
 			pc.t.cancelRequest(rc.cancelKey, rc.req.Context().Err())
 		case <-pc.closech:
 			alive = false
-			pc.t.setReqCanceler(rc.cancelKey, nil)
 		}
 
 		testHookReadLoopBeforeNextRead()

src/net/http/transport_test.go

@@ -6810,55 +6810,3 @@ func testRequestSanitization(t *testing.T, mode testMode) {
 		resp.Body.Close()
 	}
 }
-
-// Issue 61708
-func TestTransportAndServerSharedBodyReqCancelerCleanupOnConnectionClose(t *testing.T) {
-	run(t, testTransportAndServerSharedBodyReqCancelerCleanupOnConnectionClose, []testMode{http1Mode})
-}
-func testTransportAndServerSharedBodyReqCancelerCleanupOnConnectionClose(t *testing.T, mode testMode) {
-	const bodySize = 1 << 20
-
-	backend := newClientServerTest(t, mode, HandlerFunc(func(rw ResponseWriter, req *Request) {
-		io.Copy(rw, req.Body)
-	}))
-	t.Logf("Backend address: %s", backend.ts.Listener.Addr().String())
-
-	var proxy *clientServerTest
-	proxy = newClientServerTest(t, mode, HandlerFunc(func(rw ResponseWriter, req *Request) {
-		breq, _ := NewRequest("POST", backend.ts.URL, req.Body)
-
-		bresp, err := backend.c.Do(breq)
-		if err != nil {
-			t.Fatalf("Unexpected proxy outbound request error: %v", err)
-		}
-		defer bresp.Body.Close()
-
-		_, err = io.Copy(rw, bresp.Body)
-		if err == nil {
-			t.Fatalf("Expected proxy copy error")
-		}
-		t.Logf("Proxy copy error: %v", err)
-	}))
-	t.Logf("Proxy address: %s", proxy.ts.Listener.Addr().String())
-
-	req, _ := NewRequest("POST", proxy.ts.URL, io.LimitReader(neverEnding('a'), bodySize))
-	res, err := proxy.c.Do(req)
-	if err != nil {
-		t.Fatalf("Original request: %v", err)
-	}
-	// Close body without reading to trigger proxy copy error
-	res.Body.Close()
-
-	// Verify no outstanding requests after readLoop/writeLoop
-	// goroutines shut down.
-	waitCondition(t, 10*time.Millisecond, func(d time.Duration) bool {
-		n := backend.tr.NumPendingRequestsForTesting()
-		if n > 0 {
-			if d > 0 {
-				t.Logf("pending requests = %d after %v (want 0)", n, d)
-			}
-			return false
-		}
-		return true
-	})
-}