Depends on D20179. Ref T13088. See PHI351. See PHI1018. In various cases, unit tests names are 19 paths mashed together.
This is probably not an ideal name, and the test harness should probably pick a better name, but if users are fine with it and don't want to do the work to summarize on their own, accept them. We may summarize with "..." in some cases depending on how this fares in the UI.
The actual implementation is a separate "strings" table which is just <hash-of-string, full-string>. The unit message table can end up being mostly strings, so this should reduce storage requirements a bit.
For now, I'm not forcing a migration: new writes use the new table, existing rows retain the data. I plan to provide a migration tool, recommend migration, then force migration eventually.
Prior to that, I'm likely to move at least some other columns to use this table (e.g., lint names), since we have a lot of similar data (arbitrarily long user string constants that we are unlikely to need to search or filter).
