Increase JVM_INTERFACE_VERSION to 6 for JDK11+

[JasonFengJ9]

Increase JVM_INTERFACE_VERSION to 6 for JDK11+

This is required by JCL extension changes. In addition, minor refactoring to make Trc_SC_GetInterfaceVersion_Entry first call.
Note: changed J2SE_19 to J2SE_V11 since Java 9/10 is out of service.

Manually verified that JDK11 builds with this PR.

openjdk version "11.0.2-internal" 2019-01-15
OpenJDK Runtime Environment (build 11.0.2-internal+0-adhoc.jason.openj9-openjdk-jdk11)
Eclipse OpenJ9 VM (build master-7d048d4, JRE 11 Linux amd64-64-Bit Compressed References 20190219_000000 (JIT enabled, AOT enabled)
OpenJ9   - 7d048d4
OMR      - 6e7568d
JCL      - 455c2c3 based on jdk-11.0.2+9)

related: #4770

Reviewer: @DanHeidinga

Signed-off-by: Jason Feng fengj@ca.ibm.com

[DanHeidinga]

lgtm

Note, this is a first (?) step towards removing support for 9 / 10 from the code base as with this change, 9 is no longer viable.

[DanHeidinga]

Jenkins test sanity zlinux jdk11

[JasonFengJ9]

Note, this is a first (?) step towards removing support for 9 / 10 from the code base as with this change, 9 is no longer viable.

Yes, this is first step to remove support for Java 9/10 support. Am going to open another PR to make similar changes.

[keithc-ca]

With the mergers of the JVMs and JCLs, Java 9 and 10 won't build without additional changes.

[DanHeidinga]

updated the comment so this won't close #4770 as there may be additional things needed for the interface version