Fixed mockReturnValue overriding mockImplementationOnce

[grosto]

Summary

Fixes #8376. I have removed defaultReturnValue and instead mockReturnValue now uses mockImplementation under the hood. I might be missing some context, but I think this is a much more straightforward way to manage the order of mock implementations.

Test plan

Added related tests.

[codecov-io]

Codecov Report

Merging #8398 into master will decrease coverage by 0.03%.
The diff coverage is 90.9%.

@@            Coverage Diff            @@
##           master   #8398      +/-   ##
=========================================
- Coverage   62.34%   62.3%   -0.04%     
=========================================
  Files         266     266              
  Lines       10736   10722      -14     
  Branches     2611    2608       -3     
=========================================
- Hits         6693    6680      -13     
  Misses       3460    3460              
+ Partials      583     582       -1

Impacted Files	Coverage Δ
packages/jest-mock/src/index.ts	76.87% <90.9%> (-0.65%)	⬇️

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[jeysal]

This does seem like the way more obvious implementation anyway, I'm wondering if there's a reason it was not done this way.
@scotthovestadt can you find out if this will break FB?

[jablko]

I was just bitten by the same (almost) thing:

expect(
  jest
    .fn()
    .mockImplementationOnce(() => {
      throw new Error('first call');
    })
    .mockReturnValueOnce('second call')
).toThrow('first call');

[jeysal]

Sorry, the comment just brought this back on my radar. I'll request a few more reviews. This will have to wait some longer anyway though - because it's breaking it can only go in Jest 25.

[jeysal]

'or specific return values are used up' no longer seems accurate

[SimenB]

Less code which fixes a bug? I like it! Also interested if this breaks FB, though

(Needs a rebase)

[github-actions]

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