RFR: 8264809: test-lib fails to build due to some warnings in ASN1Formatter and jfr

[Jie Fu]

Hi all,

test-lib fails to build due to three javac warnings:

-------------

Commit messages:
 - 8264809: test-lib fails to build due to some warnings in ASN1Formatter and jfr

Changes: https://git.openjdk.java.net/jdk/pull/3367/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3367&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8264809
  Stats: 5 lines in 3 files changed: 1 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3367.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3367/head:pull/3367

PR: https://git.openjdk.java.net/jdk/pull/3367