[jdk11u-dev] RFR: 8286030: Avoid JVM crash when containers share the same /tmp dir

[Goetz Lindenmaier]

I backport this for parity with 11.0.19-oracle.

In 11, there is a perfMem file in each os directory.
In 17, they were merged into a single file in posix, which is touched by the original 
change backported here.
So I had to distribute the changes to multiple files.
But the changes would have applied clean.  On top, 
I "evaluated" the ifdef LINUX statements accordingly.
I edited aix, bsd and linux. On aix, I checked the build
is still working.  bsd and linux get the ususal testing.
As I have no means at all to test Solaris, i left it out.
This does not matter funcionally, because the changes
out of the #ifdef Linux parts are cosmetic improvements.

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Commit messages:
 - Fix whitespace
 - Backport d52e18c92d307f5f6e9e649d410a54bef3a910da

Changes: https://git.openjdk.org/jdk11u-dev/pull/1716/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1716&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8286030
  Stats: 451 lines in 5 files changed: 288 ins; 64 del; 99 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1716.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1716/head:pull/1716

PR: https://git.openjdk.org/jdk11u-dev/pull/1716