Test: Refactor events.js and callbacks.js to regular fixtures

In particular, events.js was the only test we had in which a QUnit
test was loading another QUnit instance. This fails as-is after the
"Always define globalThis.QUnit" patch for
#1551, because it would return
the instance that's already running instead of a separate one.

It will still be possible to do this, by adding `delete global.QUnit`
before the import, but that's not the purpose of the events test.
Instead, I've added a separate test that proves inception works.

test/cli/cli-main.js

@@ -54,176 +54,6 @@ ok 3 config
 # exit code: 1`);
   });
 
-  QUnit.test('callbacks', async assert => {
-    const expected = `CALLBACK: begin1
-CALLBACK: begin2
-CALLBACK: moduleStart1
-CALLBACK: moduleStart2
-CALLBACK: testStart1
-CALLBACK: testStart2
-CALLBACK: module1 > before
-CALLBACK: module1 > beforeEach
-TEST: module1 > test1
-CALLBACK: log1
-CALLBACK: log2
-CALLBACK: module1 > afterEach
-CALLBACK: testDone1
-CALLBACK: testDone2
-CALLBACK: moduleStart1
-CALLBACK: moduleStart2
-CALLBACK: testStart1
-CALLBACK: testStart2
-CALLBACK: module2 > before
-CALLBACK: module1 > beforeEach
-CALLBACK: module2 > beforeEach
-TEST: module2 > test1
-CALLBACK: log1
-CALLBACK: log2
-CALLBACK: module2 > afterEach
-CALLBACK: module1 > afterEach
-CALLBACK: module2 > after
-CALLBACK: testDone1
-CALLBACK: testDone2
-CALLBACK: moduleDone1
-CALLBACK: moduleDone2
-CALLBACK: moduleStart1
-CALLBACK: moduleStart2
-CALLBACK: testStart1
-CALLBACK: testStart2
-CALLBACK: module3 > before
-CALLBACK: module1 > beforeEach
-CALLBACK: module3 > beforeEach
-TEST: module3 > test1
-CALLBACK: log1
-CALLBACK: log2
-CALLBACK: module3 > afterEach
-CALLBACK: module1 > afterEach
-CALLBACK: module3 > after
-CALLBACK: testDone1
-CALLBACK: testDone2
-CALLBACK: moduleDone1
-CALLBACK: moduleDone2
-CALLBACK: testStart1
-CALLBACK: testStart2
-CALLBACK: module1 > beforeEach
-TEST: module1 > test2
-CALLBACK: log1
-CALLBACK: log2
-CALLBACK: module1 > afterEach
-CALLBACK: testDone1
-CALLBACK: testDone2
-CALLBACK: moduleStart1
-CALLBACK: moduleStart2
-CALLBACK: testStart1
-CALLBACK: testStart2
-CALLBACK: module4 > before
-CALLBACK: module1 > beforeEach
-CALLBACK: module4 > beforeEach
-TEST: module4 > test1
-CALLBACK: log1
-CALLBACK: log2
-CALLBACK: module4 > afterEach
-CALLBACK: module1 > afterEach
-CALLBACK: module4 > after
-CALLBACK: module1 > after
-CALLBACK: testDone1
-CALLBACK: testDone2
-CALLBACK: moduleDone1
-CALLBACK: moduleDone2
-CALLBACK: moduleDone1
-CALLBACK: moduleDone2
-CALLBACK: done1
-CALLBACK: done2`;
-
-    const command = ['qunit', 'callbacks.js'];
-    const execution = await execute(command);
-
-    assert.equal(execution.stderr, expected);
-    assert.equal(execution.code, 0);
-  });
-
-  QUnit.test('callbacks with promises', async assert => {
-    const expected = `CALLBACK: begin
-CALLBACK: begin2
-CALLBACK: moduleStart
-CALLBACK: moduleStart
-CALLBACK: testStart - test1
-CALLBACK: testDone - test1
-CALLBACK: moduleDone - module1 > nestedModule1
-CALLBACK: testStart - test2
-CALLBACK: testDone - test2
-CALLBACK: moduleStart
-CALLBACK: testStart - test3
-CALLBACK: testDone - test3
-CALLBACK: moduleDone - module1 > nestedModule2
-CALLBACK: moduleDone - module1
-CALLBACK: done`;
-
-    const command = ['qunit', 'callbacks-promises.js'];
-    const execution = await execute(command);
-
-    assert.equal(execution.stderr, expected);
-    assert.equal(execution.code, 0);
-  });
-
-  QUnit.test('global hooks order', async assert => {
-    const expected = `
-HOOK: A1 @ global beforeEach-1
-HOOK: A1 @ global beforeEach-2
-HOOK: A1 @ global afterEach-2
-HOOK: A1 @ global afterEach-1
-HOOK: B1 @ B before
-HOOK: B1 @ global beforeEach-1
-HOOK: B1 @ global beforeEach-2
-HOOK: B1 @ B beforeEach
-HOOK: B1 @ B afterEach
-HOOK: B1 @ global afterEach-2
-HOOK: B1 @ global afterEach-1
-HOOK: B2 @ global beforeEach-1
-HOOK: B2 @ global beforeEach-2
-HOOK: B2 @ B beforeEach
-HOOK: B2 @ B afterEach
-HOOK: B2 @ global afterEach-2
-HOOK: B2 @ global afterEach-1
-HOOK: BC1 @ BC before
-HOOK: BC1 @ global beforeEach-1
-HOOK: BC1 @ global beforeEach-2
-HOOK: BC1 @ B beforeEach
-HOOK: BC1 @ BC beforeEach
-HOOK: BC1 @ BC afterEach
-HOOK: BC1 @ B afterEach
-HOOK: BC1 @ global afterEach-2
-HOOK: BC1 @ global afterEach-1
-HOOK: BC2 @ global beforeEach-1
-HOOK: BC2 @ global beforeEach-2
-HOOK: BC2 @ B beforeEach
-HOOK: BC2 @ BC beforeEach
-HOOK: BC2 @ BC afterEach
-HOOK: BC2 @ B afterEach
-HOOK: BC2 @ global afterEach-2
-HOOK: BC2 @ global afterEach-1
-HOOK: BCD1 @ BCD before
-HOOK: BCD1 @ global beforeEach-1
-HOOK: BCD1 @ global beforeEach-2
-HOOK: BCD1 @ B beforeEach
-HOOK: BCD1 @ BC beforeEach
-HOOK: BCD1 @ BCD beforeEach
-HOOK: BCD1 @ BCD afterEach
-HOOK: BCD1 @ BC afterEach
-HOOK: BCD1 @ B afterEach
-HOOK: BCD1 @ global afterEach-2
-HOOK: BCD1 @ global afterEach-1
-HOOK: BCD1 @ BCD after
-HOOK: BCD1 @ BC after
-HOOK: BCD1 @ B after`;
-
-    const command = ['qunit', 'hooks-global-order.js'];
-    const execution = await execute(command);
-
-    assert.equal(execution.stderr, expected.trim());
-    assert.equal(execution.code, 0);
-  });
-
   // TODO: Move to /test/cli/fixtures/
   QUnit.test('run ESM test suite with import statement', async assert => {
     const command = ['qunit', '../../es2018/esm.mjs'];