RFR: 8304006: jlink should create the jimage file in the native endian for the target platform [v11]

[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 four additional commits since the last revision:

 - when --endian is specified, verify it matches the implicitly determined target platform's endianness
 - trim down the architecture support to the previous values plus a few new that match target.properties
 - improve error messages as suggested by Mandy
 - formatting fix

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11943/files
  - new: https://git.openjdk.org/jdk/pull/11943/files/e31ef76c..3946fe40

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11943&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11943&range=09-10

  Stats: 74 lines in 3 files changed: 34 ins; 28 del; 12 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