Update test CI

[BNAndras]

Related to #463.

The script wasn't cleaning up its temporary folders so the accumulate node_modules folders were piling up. By the time it got to word-count, the runner hit its disk quota.

In this PR, I made sure we erase the temp folder after a successful or failed run. I also relaxed npm's verbose logging so it looks more like this.

Testing ./exercises/practice/change
Dependency on @glennsl/bs-jest
bsb: [5/5] src/jest.cmj                                                                                                                                                                  
bsb: [7/7] install.stamp                                                                                                                                                                 
Dependency Finished
bsb: [9/9] __tests__/Change_test-Change.cmj                                                                                                                                              
 PASS  __tests__/Change_test.bs.js
  Change
    √ single coin change (2 ms)
    √ multiple coin change
    √ change with Lilliputian Coins (1 ms)
    √ change with Lower Elbonia Coins
    √ large target values (4 ms)
    √ possible change without unit coins available
    √ another possible change without unit coins available (1 ms)
    √ no coins make 0 change
    √ error testing for change smaller than the smallest of coins
    √ error if no combination can add up to target
    √ cannot find negative change values

Test Suites: 1 passed, 1 total
Tests:       11 passed, 11 total
Snapshots:   0 total
Time:        4.665 s
Ran all test suites.

[BNAndras]

@IsaacG, would you mind taking a look at the proposed changes? Thanks in advance.

[IsaacG]

The CI is failing

[IsaacG]

Failing CI aside, this looks reasonable to me.

[BNAndras]

Figures. It looks like a missing lock file that the previous CI should have caught.