Case-fold column and bean property names with Locale.ROOT (1.X)

[rootvector2]

Port of #415 to 1.X. JDBCDynaClass.createDynaProperty folds JDBC column names to lower case with String.toLowerCase(), and DefaultBeanIntrospector.handleIndexedPropertyDescriptors upper-cases the first letter of an indexed property name with String.toUpperCase(), both using the default locale. Under a Turkish locale "ID".toLowerCase() is "ıd" (dotless i), so a column ID maps to property ıd and getDynaProperty("id") returns null; the introspector likewise rebuilds an indexed accessor as getİmages instead of getImages. Both now fold with Locale.ROOT, same as the fix merged on master.

Per the review on #415, the regression test uses @DefaultLocale from JUnit Pioneer instead of saving and restoring the default locale by hand; junit-pioneer 1.9.1 (the last Java 8 compatible line) is added as a test dependency. The test fails on 1.X without the runtime change and passes with it.

Note: mvn test on a clean 1.X checkout fails LocaleBeanificationTest#testContextClassloaderIndependence in my environment (it passes in isolation and CI on 1.X is green), so I could not get a fully green default-goal run locally; the failure is identical with and without this change.

• Read the contribution guidelines for this project.
• Read the ASF Generative Tooling Guidance if you use Artificial Intelligence (AI).
• I used AI to create any part of, or all of, this pull request. Which AI tool was used to create this pull request, and to what extent did it contribute?
• Run a successful build using the default Maven goal with mvn; that's mvn on the command line by itself.
• Write unit tests that match behavioral changes, where the tests fail if the changes to the runtime are not applied. This may not always be possible, but it is a best practice.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Each commit in the pull request should have a meaningful subject line and body. Note that a maintainer may squash commits during the merge process.