RFR: 8260522: Clean up warnings in hotspot JTReg runtime tests

[Harold Seigel]

Please review this fix to clean up some of the warnings generated when running hotspot/jtreg/runtime tests.  This fix cleans up warnings such as:
    warning: [removal] Integer(int) in Integer has been deprecated and marked for removal
    warning: Main is internal proprietary API and may be removed in a future release
    warning: Option FlightRecorder was deprecated in version 13.0 ...

The fix does not clean up warnings such as the following. They should probably best be cleaned up when the deprecated items are actually removed:
    warning: [removal] suspend() in Thread has been deprecated and marked for removal
    warning: [removal] resume() in Thread has been deprecated and marked for removal
    warning: [removal] defineAnonymousClass(Class<?>,byte[],Object[]) in Unsafe has been deprecated ...
    warning: the use of signal() and sigset() for signal chaining was deprecated in version 16.0

The fix was tested by running Mach5 hs-tiers 1-3 and by running tests locally and then looking for warnings in the resulting .jtr files.

Thanks, Harold

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Commit messages:
 - 8260522: Clean up warnings in hotspot JTReg runtime tests

Changes: https://git.openjdk.java.net/jdk/pull/2293/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2293&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8260522
  Stats: 72 lines in 15 files changed: 23 ins; 12 del; 37 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2293.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2293/head:pull/2293

PR: https://git.openjdk.java.net/jdk/pull/2293