Loop over priorityConfigs seperately. The node loop can only safely
modify result[i][index]. Before this change it sometimes modified
result[i] concurrently with other loops.

Fixes: 71649676

==================== Test output for //pkg/scheduler/core:go_default_test:
==================
WARNING: DATA RACE
Read at 0x00c0005e8ed0 by goroutine 22:
  k8s.io/kubernetes/pkg/scheduler/core.PrioritizeNodes.func2()
      pkg/scheduler/core/generic_scheduler.go:667 +0x2ea
  k8s.io/kubernetes/vendor/k8s.io/client-go/util/workqueue.ParallelizeUntil.func1()
      staging/src/k8s.io/client-go/util/workqueue/parallelizer.go:65 +0x9e

Previous write at 0x00c0005e8ed0 by goroutine 21:
  k8s.io/kubernetes/pkg/scheduler/core.PrioritizeNodes.func2()
      pkg/scheduler/core/generic_scheduler.go:668 +0x450
  k8s.io/kubernetes/vendor/k8s.io/client-go/util/workqueue.ParallelizeUntil.func1()
      staging/src/k8s.io/client-go/util/workqueue/parallelizer.go:65 +0x9e

Goroutine 22 (running) created at:
  k8s.io/kubernetes/vendor/k8s.io/client-go/util/workqueue.ParallelizeUntil()
      staging/src/k8s.io/client-go/util/workqueue/parallelizer.go:57 +0x1a3
  k8s.io/kubernetes/pkg/scheduler/core.PrioritizeNodes()
      pkg/scheduler/core/generic_scheduler.go:682 +0x592
  k8s.io/kubernetes/pkg/scheduler/core.(*genericScheduler).Schedule()
      pkg/scheduler/core/generic_scheduler.go:186 +0x77d
  k8s.io/kubernetes/pkg/scheduler/core.TestGenericScheduler.func1()
      pkg/scheduler/core/generic_scheduler_test.go:464 +0x91f
  testing.tRunner()
      GOROOT/src/testing/testing.go:827 +0x162

Goroutine 21 (running) created at:
  k8s.io/kubernetes/vendor/k8s.io/client-go/util/workqueue.ParallelizeUntil()
      staging/src/k8s.io/client-go/util/workqueue/parallelizer.go:57 +0x1a3
  k8s.io/kubernetes/pkg/scheduler/core.PrioritizeNodes()
      pkg/scheduler/core/generic_scheduler.go:682 +0x592
  k8s.io/kubernetes/pkg/scheduler/core.(*genericScheduler).Schedule()
      pkg/scheduler/core/generic_scheduler.go:186 +0x77d
  k8s.io/kubernetes/pkg/scheduler/core.TestGenericScheduler.func1()
      pkg/scheduler/core/generic_scheduler_test.go:464 +0x91f
  testing.tRunner()
      GOROOT/src/testing/testing.go:827 +0x162
==================
--- FAIL: TestGenericScheduler (0.01s)
    --- FAIL: TestGenericScheduler/test_6 (0.00s)
        testing.go:771: race detected during execution of test
    testing.go:771: race detected during execution of test
FAIL