A review of the import found ways for a failure to disappear or for the
import to reach too far.

- CTRF's retryAttempts ends before the final attempt, which was dropped when
  its outcome matched the one before it.
- TAP names tests only within a stream, so a failure in one file and a pass
  under the same name in another merged into a flaky pass. The path given to
  --import is now the class of a stream's tests.
- A failure followed by a skip with the same identifier read as skipped.
- Directives are whole words: TODOING is not TODO. SKIPPED and SKIPPING stay
  directives, as harnesses treat them.
- Verdicts that alternate count as flaky only under an explicit
  --import-revision. HEAD says nothing about a dirty checkout or a report from
  another one, and two such events could quarantine a real failure.
- --import-name no longer redirects the history of a normal test run.
- Importing does not depend on the tests registered in the binary.

Tests Catch3 does not run had no history, flaky detection or quarantine.
--import=FILE reads a report instead of running tests and sends it through
the analysis, history and reports of a run: JUnit with Surefire's reruns,
xUnit.net v2, TRX, TAP 12 to 14, CTRF, Catch3's own --json report and
catch3-results, a small JSON Lines format for tools with none of these.

Results that share an identifier are attempts at one test, so a report of a
rerun gives a flaky test. --import-revision says what was tested: a verdict
that changes on one revision also counts as flaky. --import-name keeps the
results in a history of their own, which --analytics reads too. A TAP stream
that ends early fails instead of reading as a run that passed.

The amalgamation script now accepts a relative include of the third-party
wrappers, because pugixml is included from a second directory.