RFR: CODETOOLS-7903064: jcstress: Fallback topology should force NONE affinity mode

[Aleksey Shipilev]

See the bug for explanation.

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Commit messages:
 - Fix

Changes: https://git.openjdk.java.net/jcstress/pull/106/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jcstress&pr=106&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7903064
  Stats: 29 lines in 7 files changed: 26 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jcstress/pull/106.diff
  Fetch: git fetch https://git.openjdk.java.net/jcstress pull/106/head:pull/106

PR: https://git.openjdk.java.net/jcstress/pull/106