RFR: 8266822: Rename MetaspaceShared::is_old_class to has_old_class_version [v4]

[Calvin Cheung]

> Please review this simple patch for renaming the function from `MetaspaceShared::is_old_class` to `MetaspaceShared::has_old_class_version`. Also added some comment to the function.
> 
> Tests:
> - [x] tier1, 2

Calvin Cheung has updated the pull request incrementally with one additional commit since the last revision:

  move the has_old_class_version function to InstanceKlass

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3983/files
  - new: https://git.openjdk.java.net/jdk/pull/3983/files/1b90f8c4..cb45e49b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3983&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3983&range=02-03

  Stats: 61 lines in 7 files changed: 26 ins; 26 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3983.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3983/head:pull/3983

PR: https://git.openjdk.java.net/jdk/pull/3983