Allow interleaving of STDOUT and STDERR check lines. Put STDOUT lines
after the line they're attached to, and STDERR lines before. If no
STDOUT check line is attached to any line, then put them all at the end
of the file instead.
This is intended to better handle the case where stdout contains
unreplaced mentions of line numbers, and also reflects that stdout is
typically a consequence of the test rather than commentary on it, so
placing it after the test seems likely to read better.
Isolating test execution time (no build time included):
- Linux, `lit` test-per-file: Elapsed time: 28.214s, Critical Path: 13.97s
- Linux, `cc_test`-per-file: Elapsed time: 11.534s, Critical Path: 6.05s
- Linux, merged `cc_test` with 50 shards: Elapsed time: 11.677s, Critical Path: 11.17s
- Mac, `lit` test-per-file: Elapsed time: 295.686s, Critical Path: 20.00s
- Mac, `cc_test`-per-file: Elapsed time: 55.788s, Critical Path: 3.81s
- Mac, merged `cc_test` with 50 shards: Elapsed time: 16.269s, Critical Path: 7.54s
In GH actions:
- [Before](https://github.com/carbon-language/carbon-lang/actions/runs/4866602695/jobs/8678306144?pr=2799):
- test / test (ubuntu-22.04, fastbuild) (pull_request_target) Successful in 20m
- test / test (ubuntu-22.04, opt) (pull_request_target) Successful in 15m
- test / test (macos-12, fastbuild) (pull_request_target) Successful in 36m
- test / test (macos-12, opt) (pull_request_target) Successful in 21m
- [After](https://github.com/carbon-language/carbon-lang/actions/runs/4875154751/jobs/8697004066?pr=2811):
- test / test (ubuntu-22.04, fastbuild) (pull_request_target) Successful in 10m
- test / test (ubuntu-22.04, opt) (pull_request_target) Successful in 9m
- test / test (macos-12, fastbuild) (pull_request_target) Successful in 12m
- test / test (macos-12, opt) (pull_request_target) Successful in 9m
I'm still leaving a handful of `lit` tests to test end-to-end binary execution. This is why testdata directories are split (`lit` tests next to the `explorer` binary, the `cc_test`s next to `ParseAndExecute`).
This case previously crashed. Trying to handle allow_implicit_conversion better per discussion; I've split out the for loop for each path because I think it's now clearer this way.
Richard Smith
Jon Ross-Perkins