RFR: 8370978: Zero JVM fails to build on i386 after JDK-8351149

[Vladimir Petko]

This PR partially reverts  JDK-8351149 to restore zero build on 32 bit platforms.

Reverted changes to:
 -` os::dll_load`, `os::Linux::dlopen_helper`  - the functions  required to load the shared libraries

Testing (in Ubuntu 26.04 i386 chroot):

$ sh configure --with-jvm-variants=zero --disable-precompiled-headers  --with-jtreg=/home/vladimirp/git/jtreg/build/images/jtreg --disable-warnings-as-errors
...
$ make images
Building target 'images' in configuration 'linux-x86-zero-release'
Warning: No SCM configuration present and no .src-rev
Updating images/sec-bin.zip
Finished building target 'images' in configuration 'linux-x86-zero-release'
$

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

Commit messages:
 - fix: partially revert jdk-8351148 to restore zero build on 32 bit platforms

Changes: https://git.openjdk.org/jdk/pull/28406/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28406&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8370978
  Stats: 12 lines in 1 file changed: 10 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/28406.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28406/head:pull/28406

PR: https://git.openjdk.org/jdk/pull/28406