Produce source maps when instrumenting code

[mbpreble]

Summary

This change generates inline and separate file source maps for the instrumented code produced when Jest runs with --coverage in the case that the code has been transformed.

While coverage reporting appears to function correctly in this case prior to this PR, debugging code under test did not work as expected, nor did stack traces emitted by errors in code under test.

Fixes #5739

Test plan

I primarily tested this by running Jest against a small test project (https://github.com/mbpreble/jest-test)

Running my local Jest branch against the project produces the expected coverage output and stack trace for the thrown error in the test code. I am also able to debug Jest using the Node debugger and hit break points in my test code:

 FAIL  ../test-project/src/app.test.ts
  hello world
    ✕ should say hello world (3ms)

  ● hello world › should say hello world

    hello world

       6 | 
       7 | export const helloWorld =  () => {
    >  8 |     throw new Error('hello world')
         |           ^
       9 | };
      10 | 
      11 | export const uncoveredCode = () => {

      at Object.<anonymous>.exports.helloWorld (app.ts:8:11)
      at Object.<anonymous> (app.test.ts:5:16)

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |      75 |      100 |      50 |      75 |                   
 app.ts   |      75 |      100 |      50 |      75 | 12                
----------|---------|----------|---------|---------|-------------------
Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        2.358s
Ran all test suites.

Unit tests have been added/modified to reflect the new source map behavior.

[codecov-io]

Codecov Report

Merging #9460 into master will increase coverage by 0.03%.
The diff coverage is 84.61%.

@@            Coverage Diff             @@
##           master    #9460      +/-   ##
==========================================
+ Coverage   64.96%   64.99%   +0.03%     
==========================================
  Files         283      283              
  Lines       12104    12108       +4     
  Branches     2990     2992       +2     
==========================================
+ Hits         7863     7870       +7     
+ Misses       3604     3603       -1     
+ Partials      637      635       -2

Impacted Files	Coverage Δ
packages/jest-transform/src/ScriptTransformer.ts	69.64% <84.61%> (+1%)	⬆️
packages/expect/src/utils.ts	96.22% <0%> (+1.25%)	⬆️

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[SimenB]

This is great, thank you! I left a couple of nits but overall this LGTM 👍

[mbpreble]

Thanks for the approval, expect to be able to work through the feedback over the next few days.

[mbpreble]

Pushed a cleanup commit addressing review feedback.

[SimenB]

Thank you! A long-standing issue, great that it's finally fixed 👍

[SimenB]

we could create a type guard function and avoid the cast, but it's not any more type safe. so meh

[SimenB]

I'm going to revert this in #9724. @mbpreble happy to re-land this if you're able to fix it! 🙂

[github-actions]

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