Revert changes made w.r.t. JDK 9

[wolfc]

With or without these changes, compiling with JDK 9 currently does not work anyway.

The actual change also causes a regression as mentioned in https://issues.jboss.org/browse/JBEAP-9670.

[ctomc]

how can this cause regression if there was no release with this changes done yet?

[ctomc]

and just checked with JDK9 b160 it builds just fine, there are two xsd compare failures, but compile / build works just fine

[wolfc]

https://issues.jboss.org/browse/JBMETA-399
Seems compiling on Ubuntu 16.04 is an issue.

1. master branch is currently the maintenance branch for EAP 7.0. It can not go beyond Java 8 and everything must be acked.
2. Compilation with JDK 9 EA 161 without the JDK 9 commits works fine. Since there is no issue reference to the original problem, I consider these changes related to a non-issue.

[wolfc]

I figured out why the build is working on JDK 9: with -source 1.8 the modular system isn't enabled.

[wolfc]

The actual regression is:

java.time.format.DateTimeParseException: Text '1990-01-01T00:00:00' could not be parsed at index 19

	at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949)
	at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
	at java.time.ZonedDateTime.parse(ZonedDateTime.java:597)
	at java.time.ZonedDateTime.parse(ZonedDateTime.java:582)
	at org.jboss.metadata.ejb.parser.spec.TimerMetaDataParser.parseDateTime(TimerMetaDataParser.java:130)

[wolfc]

Superseded by #110