RFR: 8304006: jlink should create the jimage file in the native endian for the target platform [v20]

[Jaikiran Pai]

> Can I please get a review for this change which proposes to fix the issue reported in https://bugs.openjdk.org/browse/JDK-8206890?
> 
> The `jlink` command allows a `--endian` option to specify the byte order in the generated image. Before this change, when such a image was being launched, the code would assume the byte order in the image to be the native order of the host where the image is being launched. That would result in failure to launch java, as noted in the linked issue.
> 
> The commit in this PR, changes relevant places to not assume native order and instead determine the byte order by reading the magic bytes in the image file's header content.
> 
> A new jtreg test has been added which reproduces the issue and verifies the fix.

Jaikiran Pai has updated the pull request incrementally with six additional commits since the last revision:

 - include a test to verify that an explicitly specified --endian value which matches the target platform's endianness, creates the image correctly
 - Roger's suggestion - use Architecture.lookupByName() instead of dealing with alias name replacements
 - Determine the target platform outside of the ImageHelper and just pass it the determined target platform
 - minor formatting change - align parameters
 - Mandy's suggestion - rename (and update comments) isJavaBaseFromCurrentPlatform to isJavaBaseFromDefaultModulePath
 - Mandy's suggestion - no need to store endian in JLinkConfiguration

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11943/files
  - new: https://git.openjdk.org/jdk/pull/11943/files/962d542d..733e7b50

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11943&range=19
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11943&range=18-19

  Stats: 235 lines in 6 files changed: 119 ins; 101 del; 15 mod
  Patch: https://git.openjdk.org/jdk/pull/11943.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/11943/head:pull/11943

PR: https://git.openjdk.org/jdk/pull/11943