RFR: 8283298: Make CodeCacheSegmentSize a product flag [v2]

[Jie Fu]

> Hi all,
> 
> As discussed in https://github.com/openjdk/jdk/pull/7830, this patch makes `CodeCacheSegmentSize` a product flag.
> It also fixes two bugs when testing the release VM with CodeEntryAlignment={512, 1024}.
> Please review it.
> 
> Thanks.
> Best regards,
> Jie

Jie Fu has updated the pull request incrementally with one additional commit since the last revision:

  Add comments

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7851/files
  - new: https://git.openjdk.java.net/jdk/pull/7851/files/c84c659c..af65cbaa

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7851&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7851&range=00-01

  Stats: 4 lines in 2 files changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7851.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7851/head:pull/7851

PR: https://git.openjdk.java.net/jdk/pull/7851