RFR: CODETOOLS-7902848: jcstress: remove VM batching support [v2]

[Aleksey Shipilev]

> jcstress allows running multiple test per VM in order to optimize run times. Unfortunately, this feature gets in the way for reproducibility (multiple test contaminate the VM), error reporting (runner has to guess which test failed), and new features (like controlling the compilers). Thus, it is should go.

Aleksey Shipilev has updated the pull request incrementally with two additional commits since the last revision:

 - Make sanity test run some iterations
 - Run sanity tests in non-forked mode to make it faster

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Changes:
  - all: https://git.openjdk.java.net/jcstress/pull/10/files
  - new: https://git.openjdk.java.net/jcstress/pull/10/files/65d2d5cb..4945affb

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jcstress&pr=10&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jcstress&pr=10&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jcstress/pull/10.diff
  Fetch: git fetch https://git.openjdk.java.net/jcstress pull/10/head:pull/10

PR: https://git.openjdk.java.net/jcstress/pull/10