Avoid looking for standard encodings in "java." modules

This is the continuation of JDK-8233884 and JDK-8271456. This change affects fewer cases so I fix all "java." modules at once.

In many places standard charsets are looked up via their names, for example:
absolutePath.getBytes("UTF-8");

This could be done more efficiently(up to x20 time faster) with use of java.nio.charset.StandardCharsets:
absolutePath.getBytes(StandardCharsets.UTF_8);

The later variant also makes the code cleaner, as it is known not to throw UnsupportedEncodingException in contrary to the former variant.

Should be tested by the tier1/tier2/tier3 tests on Linux/Windows/macOS.