RFR: 8362658: sun/security/ssl/SSLEngineImpl/* tests duplicate jvm flags

[Neha Joshi]

In this PR we have updated the code to remove the duplicate call and ensure JVM flags are added only once.

### ISSUE :- 
In the test case --> ProcessTools.createTestJavaProcessBuilder(Utils.addTestJavaOpts("SSLEngineKeyLimit", "p", args[1], args[2]));
    
-> Before executing ProcessTools.createTestJavaProcessBuilder() we are calling  ---> Utils.addTestJavaOpts() which internally call prependTestJavaOpts();

>   public static String[] addTestJavaOpts(String... userArgs) {
>         return prependTestJavaOpts(userArgs);
>     }

-> Then again inside ProcessTools.createTestJavaProcessBuilder() method we are calling Utils.prependTestJavaOpts()

> public static ProcessBuilder createTestJavaProcessBuilder(String... command) {
>         return createJavaProcessBuilder(Utils.prependTestJavaOpts(command));
>     }


Calling Utils.prependTestJavaOpts() twice leads to duplicate JVM flags (This method call-> getTestJavaOpts() the main reason for duplication and below is the implementation for the same. )

> public static String[] getTestJavaOpts() {
>         List<String> opts = new ArrayList<String>();
>         Collections.addAll(opts, safeSplitString(VM_OPTIONS));
>         Collections.addAll(opts, safeSplitString(JAVA_OPTIONS));
>         return opts.toArray(new String[0]);
>     }

Contributed-by: @Korov 
https://github.com/openjdk/jdk/pull/26404

https://bugs.openjdk.org/browse/JDK-8362658

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

Commit messages:
 - JDK-8362658 : Added back the space.
 - Merge branch 'openjdk:master' into JDK-8362658/Open/Duplicate_JVM_flags
 - JDK-8362658 : Updated copyright and removed unused import.
 - JDK-8362658 : Updated code to remove duplicate jvm flags.

Changes: https://git.openjdk.org/jdk/pull/28428/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28428&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8362658
  Stats: 24 lines in 7 files changed: 0 ins; 17 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/28428.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28428/head:pull/28428

PR: https://git.openjdk.org/jdk/pull/28428