RFR: 8331391: Enhance the keytool code by invoking the buildTrustedCerts method for essential options

[Prasadrao Koppula]

Updated the code to call buildTrustedCerts only when the -trustcacerts option is specified

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Commit messages:
 - JDK-8331391

Changes: https://git.openjdk.org/jdk/pull/21058/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21058&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331391
  Stats: 2 lines in 1 file changed: 1 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21058.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21058/head:pull/21058

PR: https://git.openjdk.org/jdk/pull/21058