[crac] RFR: 8349131: [CRaC] Internal error on old glibc with pre-set GLIBC_TUNABLES and CPUFeatures restriction

[Timofei Pushkin]

Besides fixing the issue adds a corresponding test case.

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Commit messages:
 - Add missing error message ending
 - Add suggested parantheses
 - CRaC: CPUFeatures: error on centos7 build with pre-set env GLIBC_TUNABLES and -XX:CPUFeatures=generic

Changes: https://git.openjdk.org/crac/pull/200/files
  Webrev: https://webrevs.openjdk.org/?repo=crac&pr=200&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349131
  Stats: 19 lines in 2 files changed: 17 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/crac/pull/200.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/200/head:pull/200

PR: https://git.openjdk.org/crac/pull/200