RFR: 8269424: Some SuppressWarnings annotations can be more localized

[Kevin Rushforth]

This is a follow-on fix to [JDK-8264139](https://bugs.openjdk.java.net/browse/JDK-8264139), which added `@SuppressWarning` annotations to usages of deprecated security manager methods. @wangweij noticed that there was one pattern where the automated tool added the warning at a higher level than was needed. This fix moves the annotation down to me more localized in the two places that were affected.

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Commit messages:
 - 8269424: Some SuppressWarnings annotations can be more localized

Changes: https://git.openjdk.java.net/jfx/pull/546/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=546&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8269424
  Stats: 4 lines in 2 files changed: 2 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/546.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/546/head:pull/546

PR: https://git.openjdk.java.net/jfx/pull/546