Fixes to config file and flakiness fix for TestFloatValueDefault

[GuptaManan100]

Description

This PR address 3 fixes to the CI -

1. TestFloatValueDefault was flaky since it didn't specifically order the results of the query leading to rows order being different from the expectations. The fix entails adding an order by clause to make the row order deterministic.
2. tabletgateway_cellalias config from config.json has been removed. The package of tests being run by this config do not exist. We see the following lines in the CI

   running tests for  vitess.io/vitess/go/test/endtoend/tabletgateway/cellalias
   [4243](https://github.com/vitessio/vitess/runs/7340550027?check_suite_focus=true#step:10:4244)
   no required module provides package vitess.io/vitess/go/test/endtoend/tabletgateway/cellalias; to add it:
   [4244](https://github.com/vitessio/vitess/runs/7340550027?check_suite_focus=true#step:10:4245)
        go get vitess.io/vitess/go/test/endtoend/tabletgateway/cellalias
   

3. vtgate_buffer test has been removed. Like ☝️, it too tries to run tests that don't exist.4.

   2022/07/14 13:17:03 ============================================================
   [30](https://github.com/vitessio/vitess/runs/7340548461?check_suite_focus=true#step:9:31)
   2022/07/14 13:17:03 local.vtgate_buffer                     	FAIL (1 tries)
   [31](https://github.com/vitessio/vitess/runs/7340548461?check_suite_focus=true#step:9:32)
   2022/07/14 13:17:03 ============================================================
   [32](https://github.com/vitessio/vitess/runs/7340548461?check_suite_focus=true#step:9:33)
   2022/07/14 13:17:03 0 PASSED, 0 FLAKY, 1 FAILED, 0 SKIPPED
   2022/07/14 13:17:03 ============================================================
   [30](https://github.com/vitessio/vitess/runs/7340548461?check_suite_focus=true#step:9:31)
   2022/07/14 13:17:03 local.vtgate_buffer                     	FAIL (1 tries)
   [31](https://github.com/vitessio/vitess/runs/7340548461?check_suite_focus=true#step:9:32)
   2022/07/14 13:17:03 ============================================================
   [32](https://github.com/vitessio/vitess/runs/7340548461?check_suite_focus=true#step:9:33)
   2022/07/14 13:17:03 0 PASSED, 0 FLAKY, 1 FAILED, 0 SKIPPED
   

Related Issue(s)

Checklist

• "Backport me!" label has been added if this change should be backported
• Tests were added or are not required
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

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[rohit-nayak-ps]

lgtm

[GuptaManan100]

@deepthi The vtgate_buffer test has to be removed from the required list of tests for us to be able to merge this PR.