Fixes for Betula Lloyd k-means

[andiwg]

This fixes the incorrect usage of the naive flag. The previous version did only disregard the weight when initializing the result arrays.

It also adds missing timings that are present for other k-means algorithms.

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 52.40%. Comparing base (550de99) to head (a6d3162).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
...java/elki/clustering/kmeans/BetulaLloydKMeans.java	75.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #118      +/-   ##
============================================
- Coverage     52.41%   52.40%   -0.01%     
+ Complexity    12833    12832       -1     
============================================
  Files          1846     1846              
  Lines         93979    93981       +2     
  Branches      17468    17468              
============================================
- Hits          49256    49252       -4     
- Misses        40397    40400       +3     
- Partials       4326     4329       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.