Add --cancel-scheduled flag to cancel all existing scheduled stops

[priyawadhwa]

output looks like:

$ minikube stop --cancel-scheduled
🛑  All existing scheduled stops cancelled

adds to integration test to make sure this flag works as expected.

fixes #9730

[priyawadhwa]

/ok-to-test

[minikube-pr-bot]

kvm2 Driver
error collecting results for kvm2 driver: timing run 0 with Minikube (PR 9774): timing cmd: [/home/performance-monitor/.minikube/minikube-binaries/9774/minikube start --driver=kvm2]: starting cmd: fork/exec /home/performance-monitor/.minikube/minikube-binaries/9774/minikube: exec format error
docker Driver
error collecting results for docker driver: timing run 0 with Minikube (PR 9774): timing cmd: [/home/performance-monitor/.minikube/minikube-binaries/9774/minikube start --driver=docker]: starting cmd: fork/exec /home/performance-monitor/.minikube/minikube-binaries/9774/minikube: exec format error

[minikube-pr-bot]

kvm2 Driver
Times for minikube: 64.4s 54.6s 54.1s
Average time for minikube: 57.7s

Times for Minikube (PR 9774): 55.2s 54.6s 54.1s
Average time for Minikube (PR 9774): 54.6s

Averages Time Per Log

+--------------------------------+----------+--------------------+
|              LOG               | MINIKUBE | MINIKUBE (PR 9774) |
+--------------------------------+----------+--------------------+
| * minikube v1.15.1 on Debian   | 0.0s     | 0.0s               |
|                           9.11 |          |                    |
| * Using the kvm2 driver based  | 0.0s     | 0.0s               |
| on user configuration          |          |                    |
| * Starting control plane node  | 0.0s     | 0.0s               |
| minikube in cluster minikube   |          |                    |
| * Creating kvm2 VM (CPUs=2,    | 32.9s    | 31.5s              |
| Memory=3700MB, Disk=20000MB)   |          |                    |
| ...                            |          |                    |
| * Preparing Kubernetes v1.19.4 | 22.9s    | 21.2s              |
| on Docker 19.03.13 ...         |          |                    |
| * Verifying Kubernetes         | 1.5s     | 1.5s               |
| components...                  |          |                    |
| * Enabled addons:              | 0.4s     | 0.5s               |
| storage-provisioner,           |          |                    |
| default-storageclass           |          |                    |
|                                | 0.1s     | 0.0s               |
|   - Want kubectl v1.19.4? Try  |          |                    |
| 'minikube kubectl -- get pods  |          |                    |
| -A'                            |          |                    |
| * Done! kubectl is now         |          |                    |
| configured to use "minikube"   |          |                    |
| cluster and "default"          |          |                    |
| namespace by default           |          |                    |
+--------------------------------+----------+--------------------+

docker Driver
Times for minikube: 28.7s 28.4s 28.0s
Average time for minikube: 28.4s

Times for Minikube (PR 9774): 30.0s 27.9s 27.3s
Average time for Minikube (PR 9774): 28.4s

Averages Time Per Log

+--------------------------------+----------+--------------------+
|              LOG               | MINIKUBE | MINIKUBE (PR 9774) |
+--------------------------------+----------+--------------------+
| * minikube v1.15.1 on Debian   | 0.2s     | 0.2s               |
|                           9.11 |          |                    |
| * Using the docker driver      | 0.1s     | 0.1s               |
| based on user configuration    |          |                    |
| * Starting control plane node  | 0.1s     | 0.1s               |
| minikube in cluster minikube   |          |                    |
| * Creating docker container    | 8.8s     | 8.9s               |
| (CPUs=2, Memory=3700MB) ...    |          |                    |
| * Preparing Kubernetes v1.19.4 | 18.0s    | 18.1s              |
| on Docker 19.03.13 ...         |          |                    |
| * Verifying Kubernetes         | 1.1s     | 1.0s               |
| components...                  |          |                    |
| * Enabled addons:              | 0.1s     | 0.1s               |
| storage-provisioner,           |          |                    |
| default-storageclass           |          |                    |
|                                | 0.0s     | 0.0s               |
|   - Want kubectl v1.19.4? Try  |          |                    |
| 'minikube kubectl -- get pods  |          |                    |
| -A'                            |          |                    |
| * Done! kubectl is now         |          |                    |
| configured to use "minikube"   |          |                    |
| cluster and "default"          |          |                    |
| namespace by default           |          |                    |
+--------------------------------+----------+--------------------+

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: medyagh, priyawadhwa

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[medyagh]

/retest-this-please