Add test sizes to small test targets.

[eljobe]

This will cause us to deliberately decide if we need to increase the
test size if they get bigger. It also prevents a warning in the
output of bazel test //...

Intentionally ignoring the in-progress cache as it is going away
in #689

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.82%. Comparing base (782f09f) to head (a120fdb).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #690      +/-   ##
==========================================
- Coverage   60.09%   59.82%   -0.28%     
==========================================
  Files          50       50              
  Lines        8759     8759              
==========================================
- Hits         5264     5240      -24     
- Misses       3488     3513      +25     
+ Partials        7        6       -1