RFR: 8327045: Consolidate -fvisibility=hidden as a basic flag for all compilation [v2]

[Magnus Ihse Bursie]

> After we removed mapfiles, we can setup -fvisibility=hidden (and -Wl,--exclude-libs,ALL) in the most basic flags, so this applies to all compilation.
> 
> This will remove duplicate code and make the underlying assumptions of the build clearer.
> 
> Doing this will result in the same output result -- with one exception: native test libraries has not been compiled with this flag (and this caused an error for a Oracle-internal test).

Magnus Ihse Bursie has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18061/files
  - new: https://git.openjdk.org/jdk/pull/18061/files/350fcb5d..350fcb5d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18061&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18061&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18061.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18061/head:pull/18061

PR: https://git.openjdk.org/jdk/pull/18061