RFR: 8257803: Add -Xbatch to compiler/blackhole tests

[Aleksey Shipilev]

Newly added tests miss `-Xbatch`, which makes them sensitive to compilation delays, especially when running in parallel with many other tests. There are already failures observed in current testing. While there might be other causes, this patch eliminates the most obvious one.

The run time of the tests are not affected, because the tests are still small.

Testing:
 - [x] `compiler/blackhole` tests running in larger `hotspot:tier1` suite (added separately, 5 of 5 runs pass)

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Commit messages:
 - -Xbatch to make tests less sensitive to compilation delays

Changes: https://git.openjdk.java.net/jdk/pull/1653/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1653&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8257803
  Stats: 21 lines in 6 files changed: 1 ins; 0 del; 20 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1653.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1653/head:pull/1653

PR: https://git.openjdk.java.net/jdk/pull/1653