[jdk8u-dev] RFR: 8168518: rcache interop with krb5-1.15

[Alexey Bakhtin]

I'd like to backport JDK-8168518 to update rcache hash algorithm from MD5 to SHA-256. It fixes issues on the FIPS environment without MD5 digest support

Implementation classes are applied cleanly.

Test changes are merged manually:
- Changes in the Proc.java are skipped because of no module support in JDK8
- "-Dsun.net.spi.nameservice.provider.1=ns,mock" option is added to rcache_usemd5.sh
- ReplayCacheTestProc.java is merged manually because of JDK-8190690 changes in JDK8

sun/security/krb5/auto tests passed

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

Commit messages:
 - Backport e10da9956fba577bcc097b63eb3b4d09896fa77d

Changes: https://git.openjdk.org/jdk8u-dev/pull/418/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=418&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8168518
  Stats: 428 lines in 8 files changed: 261 ins; 26 del; 141 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/418.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/418/head:pull/418

PR: https://git.openjdk.org/jdk8u-dev/pull/418