Inherit "only" mode unless there is tests with "only" mode already

[doniyor2109]

Summary

Fixes #7837

Test plan

yarn test

[doniyor2109]

It is little verbose solution. Welcome to other solutions

[codecov-io]

Codecov Report

Merging #7888 into master will decrease coverage by 0.07%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #7888      +/-   ##
==========================================
- Coverage   58.15%   58.08%   -0.08%     
==========================================
  Files         173      173              
  Lines        6424     6427       +3     
  Branches        5        5              
==========================================
- Hits         3736     3733       -3     
- Misses       2686     2692       +6     
  Partials        2        2

Impacted Files	Coverage Δ
packages/jest-circus/src/utils.js	18.48% <ø> (-2.01%)	⬇️
packages/jest-circus/src/eventHandler.js	10.97% <0%> (-0.87%)	⬇️

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[SimenB]

Thanks, this looks good!

Left a comment about the integration test, beyond that this lgtm

[jeysal]

Thanks a lot for fixing this! Left some comments :)

[SimenB]

Thanks!