RFR: 8292318: Memory corruption in remove_dumptime_info

[Ioi Lam]

In [JDK-8290833](https://bugs.openjdk.org/browse/JDK-8290833) (#9759), I added a table (`SystemDictionaryShared::_saved_cpcache_entries_table`) that remembers the initial state of a `ConstantPoolCache` during CDS dumping. This table is indexed with a `ConstantPoolCache*`

However, `ConstantPoolCache` has a complex lifecycle, especially with class redefinition. This makes it difficult to clean up the table. The crash reported in [the current bug](https://bugs.openjdk.org/browse/JDK-8292318) happened during clean up, probably because an `InstanceKlass` was still valid but its `ConstantPool` or `ConstantPoolCache` were not.

For simplification, I am now storing the information inside the `ConstantPoolCache`. To compensate for the extra space used, I moved two 32-bit integers next to each other, so the net change in size is zero.

instanceKlass.cpp was reverted to the state before #9759.

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Commit messages:
 - fixed old bug in test case
 - 8292318: Memory corruption in remove_dumptime_info

Changes: https://git.openjdk.org/jdk/pull/9887/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9887&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8292318
  Stats: 106 lines in 7 files changed: 20 ins; 75 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/9887.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9887/head:pull/9887

PR: https://git.openjdk.org/jdk/pull/9887