[BUG] Performance degradation when worker scales in small datasets.

**Describe the bug**
We tested page_rank on datagen-7_5-fb.e dataset using graphscope:0.21.0 k8s mode, but it failed in add_edegs.

**To Reproduce**
Steps to reproduce the behavior:
1. create session using k8s mode
2. read the dataset
3. create graph using 'add_edges'
4. failed in 'add_edges'

**Expected behavior**
create graph successful.

**Screenshots**
We found the logs in coordinator pod in k8s. During 'add_edges', the logs show that
craete engine headless services ..
...
...
kubernetes.client.exceptions.ApiException:(409)
Reson:Conflict
..... services 'gs-engine-onmitz-headless' already exists.

At last, coordinator pod did not work.

**Environment (please complete the following information):**
- GraphScope version: [0.21.0]
- OS: [Ubuntu 20.04]
- Kubernetes Version [v1.21.4]

**Additional context**
We tested dataset 'twitter.e' on k8s mode, all is ok.
We tested dataset 'datagen-7_5-fb.e' on hosts mode, all is ok.
Maybe big dataset didnot work on k8s mode? (graphscope 0.21.0)