RFR: 8280890: Cannot use '-Djava.system.class.loader' with class loader in signed JAR [v2]

[Sean Mullan]

> This fixes a bootstrapping issue if a custom system class loader is set with the `-Djava.system.class.loader` option and the custom class loader is inside a signed JAR.  In order to load the custom class loader, the runtime must verify the signed JAR first, and the algorithm constraint code tries to load a `Locale` provider using a `ServiceLoader` before the class loader is set, and this causes a `ServiceConfigurationError`.
> 
> The fix removes a dependency from the security algorithm "denyAfter" constraint parsing code on the `Calendar` API which uses a `ServiceLoader` for gathering default locale information. Instead the `ZonedDateTime` API is now used, which simplifies the code and removes some unnecessary code from `keytool` as well.

Sean Mullan has updated the pull request incrementally with one additional commit since the last revision:

  Check exit status of keytool and jarsigner in test.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7316/files
  - new: https://git.openjdk.java.net/jdk/pull/7316/files/914c8821..a52e5137

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7316&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7316&range=00-01

  Stats: 6 lines in 1 file changed: 3 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7316.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7316/head:pull/7316

PR: https://git.openjdk.java.net/jdk/pull/7316