Fix npm test file matching on Windows

[ParkerM]

The matching pattern jest --coverage test/*.test.js no longer works with npm test on Windows (see jestjs/jest#6650). The default glob pattern in jest.config.js matches the same files in both environments, so it shouldn't be needed in the npm test script.

I also added mockCache.js to coveragePathIgnorePatterns so it would stop showing up in coverage reports.

Before (click for logs)

$ npm test

> openjdk-api@1.0.0 test C:\Users\<mypath>\openjdk-api
> jest --coverage test/*.test.js && npm run lint

No tests found, exiting with code 1
Run with `--passWithNoTests` to exit with code 0
In C:\Users\<mypath>\openjdk-api
  37 files checked.
  testMatch: **/__tests__/**/*.[jt]s?(x),**/?(*.)+(spec|test).[tj]s?(x) - 2 matches
  testPathIgnorePatterns: \\node_modules\\ - 37 matches
  testRegex:  - 37 matches
Pattern: test\\*.test.js - 0 matches
npm ERR! Test failed.  See above for more details.

After (click for logs)

$ npm test

> openjdk-api@1.0.0 test C:\Users\<mypath>\openjdk-api
> jest --coverage && npm run lint

PASS test/versions.test.js
PASS test/v2.test.js
  ● Console

    console.log app/lib/github_file_cache.js:17
      Reading auth

-----------------------|----------|----------|----------|----------|-------------------|
File                   |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-----------------------|----------|----------|----------|----------|-------------------|
All files              |    78.41 |    75.16 |    84.69 |    78.16 |                   |
 lib                   |       50 |       40 |    36.84 |       50 |                   |
  github_file_cache.js |       50 |       40 |    36.84 |       50 |... 55,166,167,179 |
 routes                |    85.46 |    81.82 |     96.2 |    85.25 |                   |
  v2.js                |    83.13 |    78.95 |    95.71 |    82.85 |... 42,543,545,546 |
  versions.js          |      100 |      100 |      100 |      100 |                   |
-----------------------|----------|----------|----------|----------|-------------------|

Test Suites: 2 passed, 2 total
Tests:       129 passed, 129 total
Snapshots:   0 total
Time:        3.088s
Ran all test suites.

> openjdk-api@1.0.0 lint C:\Users\<mypath>\openjdk-api
> eslint *.js app/routes/*.js

[karianna]

LGTM