Building or Testing on a system with default encoding other than UTF-8 breaks file "stemming_samples.txt"

[C057A5]

The problem is that UpdateStemmingSamples.java reads the file with UTF-8 encoding and replaces it with a file using the default encoding of the building computer. Subsequent builds fail.

Proposed changes (lines 27, 28):
FileOutputStream fileWriter = new FileOutputStream(file.getAbsoluteFile());
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(fileWriter, StandardCharsets.UTF_8));