File Sync fails when syncing thousands of files: kubectl argument list too long

This is issue has been created off the back of a comment in another:

https://github.com/GoogleContainerTools/skaffold/issues/531#issuecomment-668069489

### Expected behavior

FileSync should work without error

### Actual behavior

Errors happen during the File Sync:

```
time="2020-08-03T15:54:49+01:00" level=warning msg="Skipping deploy due to sync error: deleting files: starting command /usr/local/bin/kubectl --context gke_qumu-dev_europe-west1-b_qumu-dev-dev1 exec qumucloud-dfernandez-85dc9c9d85-xn9xk --namespace default -c qumucloud-dfernandez -- rm -rf -- /usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/kuluvalley/guru/server/api/cache/Delegate.class /usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/kuluvalley/guru/server/api/content/chapter/ChapterApi.class /usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/kuluvalley/guru/server/integration/stoneshot/GetSessionsInvitedForContactResponse.class /usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/kuluvalley/guru/server/security/SsoUserMapper.class /usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/kuluvalley/guru/server/security/jwt/JwtSigningException.class /usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/kuluvalley/guru/server/api/dto/AsyncJobDto.class /usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/kuluvalley/guru/server/integration/stone...
-- MANY MORE FILE PATHS --
INF/classes/com/kuluvalley/guru/server/presentation/controller/admin/MetadataTypeEnumController.class /usr/local/tomcat/webapps/ROOT/WEB-INF/classes/com/kuluvalley/guru/server/security/KeyStoreConfig.class: fork/exec /usr/local/bin/kubectl: argument list too long"
```

### Information

- Skaffold version: 1.13.1
- Operating system: Mac OSX 10.15.5
- Contents of skaffold.yaml:

```yaml
artifacts:
- image: "skaffold-qc"
context: '..'
sync:
manual:
- src: 'KVP/**/*.class'
dest: /usr/local/tomcat/webapps/ROOT
strip: 'KVP'
- src: 'KVP/client/**/*.*'
dest: /usr/local/tomcat/webapps/ROOT
strip: 'KVP'
- src: 'deploy/external-configuration/app/external-configuration/*.*'
dest: /app/external-configuration
strip: 'deploy/external-configuration/app/external-configuration'
```

### Steps to reproduce the behavior

Run skaffold command like this:

```
skaffold dev --filename skaffold.yml --profile qc --trigger=polling --cleanup=false --auto-build=false --auto-deploy=false --default-repo repo --port-forward=true --status-check=false
```