RFR: 8358159: Empty mode/padding in cipher transformations [v2]

[Varada M]

> Omitting the mode/padding in a transformation string eg: "AES/ /NoPadding" throws NoSuchAlgorithmException.
> This patch restores the behavior by ensuring that empty mode or padding strings are interpreted as null.
> 
> Testing done for : tier1 - fastdebug level (AIX)
> 
> JBS: [JDK-8358159](https://bugs.openjdk.org/browse/JDK-8358159)

Varada M has updated the pull request incrementally with one additional commit since the last revision:

  jtreg test case

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25547/files
  - new: https://git.openjdk.org/jdk/pull/25547/files/e7a35711..ccc650bb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25547&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25547&range=00-01

  Stats: 54 lines in 1 file changed: 54 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25547.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25547/head:pull/25547

PR: https://git.openjdk.org/jdk/pull/25547