Refactor Jenkins Build files

[AdamBrousseau]

Currently, we have too much duplication between our top level Jenkins build files. We need to come up with a solution to refactor these so we can reduce or eliminate this repetitive code.

Files in question:

• Build
• Test (perhaps unnecessary as we move to Adopt's test files Switch to using Adopt JenkinsFiles for Test #1450)
• Nightly Pipelines
• PullRequests (compile, sanity, extended)

One proposal is to parse the build name to set the SPEC and SDK_VERISON. Prototyped in #1396
Another option is to pass the SPEC and SDK_VERSION as build parameters.

The Build* and PullRequest-Compile* files are now identical (except for an extra timeout). So we could at least eliminate all the PullRequest-Compile files. However this would be an exception to the current convention. A larger refactor may make this irrelevant.

[AdamBrousseau]

I think I'm ok with passing them in as build parameters if we use choice params and only give one choice. That way, they can't easily be changed on the fly. Although, I'll have to try it out because when we call a Build job from an upstream pipeline, we don't pass SPEC and SDK. So I'm not sure if the defaults will be picked up. I recall a few years ago that the defaults would get ignored if you passed params and didn't pass the expected ones.

[AdamBrousseau]

#2093