Fix a warning in OldStackTraceElementTest due to missing JNI method implementation

This doesn't fix b/240239515, but just fix the warning occured
in the logs.

Bug: 240239515
Test: atest CtsLibcoreTestCases:libcore.java.lang.OldStackTraceElementTest
Change-Id: Ibba4cb9d60430c57eb1c24878421e105b8d5d5d6
3 files changed