RFR: 8344181: Remove SecurityManager and related calls from jdk.management and jdk.management.agent [v5]

[Kevin Walls]

> Remove redundant SecurityManager, AccessController references
> (following on from JDK-8338411: Implement JEP 486: Permanently Disable the Security Manager).
> 
> src/jdk.management/share/classes/com/sun/management/internal/GarbageCollectionNotifInfoCompositeData.java
> There is an existing theoretical path where GcInfoBuilder stays null, should never happen, "com.sun.management.GcInfo" exists...
> 
> src/jdk.management/share/classes/com/sun/management/internal/GcInfoCompositeData.java
> Similarly there is an existing assumption that Class.forName("com.sun.management.GcInfo") succeeds.

Kevin Walls has updated the pull request incrementally with two additional commits since the last revision:

 - newline
 - remove implSetParallelism from VSThreadSchedulers

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22155/files
  - new: https://git.openjdk.org/jdk/pull/22155/files/84d59ac3..7149d173

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22155&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22155&range=03-04

  Stats: 10 lines in 1 file changed: 1 ins; 7 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/22155.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22155/head:pull/22155

PR: https://git.openjdk.org/jdk/pull/22155