Redundant castings make code harder to read. Found them by IntelliJ IDEA. I tried to choose only casts which are definitely safe to remove. Most generification was done in [JDK-8241618](https://bugs.openjdk.org/browse/JDK-8241618), but casts weren't removed.
------------- Commit messages: - [PATCH] Remove unnecessary castings in jdk.hotspot.agent Changes: https://git.openjdk.org/jdk/pull/10295/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10295&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8293879 Stats: 261 lines in 75 files changed: 0 ins; 8 del; 253 mod Patch: https://git.openjdk.org/jdk/pull/10295.diff Fetch: git fetch https://git.openjdk.org/jdk pull/10295/head:pull/10295 PR: https://git.openjdk.org/jdk/pull/10295
