There's no option to output the results of the test262 harness in silent mode so
every pass and failure outputs multiple lines to stdout. Since there are many
thousands of tests this results in unusable log files that are over 200k lines
long. This PR redirects stdout to a tmp file and then we reformat the result
into a small JSON object, grouped by the failure message with count.
Example:
```json [ { "pass": false, "data": { "message": "Expected no
error, got Error: TODO: Support complex object assignment", "count": 66
} }, { "pass": false, "data": { "message": "Expected no
error, got Error: TODO: lowerExpression(FunctionExpression)", "count": 4
} }, { "pass": false, "data": { "message": "Expected no
error, got Error: TODO: lowerExpression(UnaryExpression)", "count": 6
} }, { "pass": false, "data": { "message": "Expected no error,
got Error: todo: lower initializer in ForStatement", "count": 28 }
}, { "pass": false, "data": { "message": "Expected no error, got
Invariant Violation: Expected value for identifier `15` to be initialized.",
"count": 14 } }, { "pass": false, "data": { "message":
"Expected no error, got Invariant Violation: `var` declarations are not
supported, use let or const", "count": 76 } }, { "pass": true,
"data": { "message": null, "count": 1 } } ] ```
Add a new workflow to run the test262 tests on commits to main but not in pull
requests. This is to keep this test non-blocking on PRs but lets us track pass
rates over time