[ty] Print salsa memory usage totals in mypy primer CI runs (#18973)

## Summary

Print the [new salsa memory usage
dumps](https://github.com/astral-sh/ruff/pull/18928) in mypy primer CI
runs to help us catch memory regressions. The numbers are rounded to the
nearest power of 1.1 (about a 5% threshold between buckets) to avoid overly sensitive diffs.

crates/ty/src/lib.rs

@@ -146,6 +146,7 @@ fn run_check(args: CheckCommand) -> anyhow::Result<ExitStatus> {
     let mut stdout = stdout().lock();
     match std::env::var("TY_MEMORY_REPORT").as_deref() {
         Ok("short") => write!(stdout, "{}", db.salsa_memory_dump().display_short())?,
+        Ok("mypy_primer") => write!(stdout, "{}", db.salsa_memory_dump().display_mypy_primer())?,
         Ok("full") => write!(stdout, "{}", db.salsa_memory_dump().display_full())?,
         _ => {}
     }