Lazily initialize DataSize.PATTERN

[sbrannen]

To avoid unnecessary eager initialization of org.springframework.util.unit.DataSize.PATTERN, we should initialize it lazily in the first invocation of DataSize.parse(CharSequence, DataUnit).

This can be achieved by moving PATTERN to a private static nested class.

See oracle/graal#4489 for details.

[sbrannen]

Related Issues:

• Work around the fact that GraalVM detects that DataSize is safe to initialize at build time #28328