RFR: 8253495: CDS generates non-deterministic output [v7]

[Ioi Lam]

> This patch makes the result of "java -Xshare:dump" deterministic:
> - Disabled new Java threads from launching. This is harmless. See comments in jvm.cpp
> - Fixed a problem in hashtable ordering in heapShared.cpp
> - BasicHashtableEntry has a gap on 64-bit platforms that may contain random bits. Added code to zero it.
> - Enabled checking of $JAVA_HOME/lib/server/classes.jsa in make/scripts/compare.sh
> 
> Note:  $JAVA_HOME/lib/server/classes_ncoops.jsa is still non-deterministic. This will be fixed in [JDK-8282828](https://bugs.openjdk.java.net/browse/JDK-8282828).
> 
> Testing under way:
> - tier1~tier5
> - Run all *-cmp-baseline jobs 20 times each (linux-aarch64-cmp-baseline, windows-x86-cmp-baseline, .... etc).

Ioi Lam has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 12 additional commits since the last revision:

 - fixed copyright
 - Merge branch 'master' into 8253495-cds-generateds-non-deterministic-output-2
 - @calvinccheung review: fixed typo
 - Added helper function CollectedHeap::zap_filler_array_with
 - @kimbarrett comments
 - zero GC heap filler arrays
 - improvement zeroing of alignment gaps
 - Fixed zero build
 - Merge branch 'master' into 8253495-cds-generateds-non-deterministic-output-2
 - fixed test
 - ... and 2 more: https://git.openjdk.java.net/jdk/compare/a6344ded...cd934f3c

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7748/files
  - new: https://git.openjdk.java.net/jdk/pull/7748/files/47e0238a..cd934f3c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7748&range=06
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7748&range=05-06

  Stats: 6804 lines in 210 files changed: 3347 ins; 1802 del; 1655 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7748.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7748/head:pull/7748

PR: https://git.openjdk.java.net/jdk/pull/7748