RFR: 8338856: [BACKOUT] JDK-8337828: CDS: Trim down minimum GC region alignment

[Aleksey Shipilev]

This reverts commit 598169756c903bb1f77e35ea32717043bc166e3c.

Causes failures in deeper testing, see [JDK-8338753](https://bugs.openjdk.org/browse/JDK-8338753).


$ CONF=linux-x86_64-server-fastdebug make test TEST=runtime/cds/appcds/LotsOfClasses.java TEST_VM_OPTS=-XX:-UseCompressedOops

java.lang.RuntimeException: Hotspot crashed
at jdk.test.lib.cds.CDSTestUtils.executeAndLog(CDSTestUtils.java:699)
at jdk.test.lib.cds.CDSTestUtils.executeAndLog(CDSTestUtils.java:675)
at jdk.test.lib.cds.CDSTestUtils.createArchive(CDSTestUtils.java:270)
at jdk.test.lib.cds.CDSTestUtils.createArchiveAndCheck(CDSTestUtils.java:306)
at LotsOfClasses.main(LotsOfClasses.java:56)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:573)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:333)
at java.base/java.lang.Thread.run(Thread.java:1575)


Additional testing:
 - [ ] Linux x86_64 server fastdebug, `runtime/cds`
 - [ ] Linux x86_64 server fastdebug, `runtime/cds` with `-XX:-UseCompressedOops`

-------------

Commit messages:
 - Revert "8337828: CDS: Trim down minimum GC region alignment"

Changes: https://git.openjdk.org/jdk/pull/20681/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20681&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338856
  Stats: 5 lines in 1 file changed: 1 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/20681.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20681/head:pull/20681

PR: https://git.openjdk.org/jdk/pull/20681