SRE-3441 Some cleanup of groovy code

[JohnMalmberg]

The Date() method is not allowed by Jenkins Sandbox and needs to be fixed.

This also fixes some diagnostics Jenkins is logging about untyped
variables in some of the groovy methods. These untyped variables
can be updated by other threads and cause intermittent failures
in Jenkins jobs.

var/Date.groovy:
Replace the Date goovy method with an equivalent library step
that is allowed in a grooy sandbox.
This is intended as a hack to compensate for Jenkinsfiles that
currently use the Date function until they can be fixed.

vars/buildRpm.groovy:
vars/durationSeconds.groovy:
vars/provisionNodes.groovy:
vars/runTest.groovy:
vars/testRpm.groovy:
Change from Date to currentTimeMillis method.

vars/cloverReportPublish.groovy:
vars/runScriptWithStashes.groovy:
vars/sconsBuild.groovy:
vars/unitTestPost.groovy:
Change from Date to currentTimeMillis method.
Make unstash failures not always fatal.
Spelling and or minor linting fixes.

vars/daosPackagesVersion.groovy:
Standardize exception for unstash error handling.

vars/functionalTest.groovy:
vars/functionalTestPostV2.groovy:
vars/unitTest.groovy:
Change from Date to currentTimeMillis method.
Remove launchable code.
Standardize exception for unstash error handling.

vars/hwDistroTarget.groovy:
vars/hwDistroTarget2.groovy:
Fix use of global untyped variables that could cause corruption.

vars/valgrindReportPublish.groovy:
Allow disabling valgrindPublish with environment variable.
Spelling and or minor linting fixes.

Jenkinsfile:
vars/junitSimpleReport.groovy:
vars/notifyBrokenBranch.groovy:
vars/runTestFunctional.groovy:
vars/runTestFunctionalV1.groovy:
vars/runTestFunctionalV2.groovy:
vars/scmNotify.groovy:
vars/testRpm.groovy:
Minor Spelling and or linting fixes.

[JohnMalmberg]

I can't seem to get a clean run on this no mattery how many times I try and none of the failures appear to be related to changes in this PR. The actual code changes in this PR cleans up Jenkins reporting a potential data corruption issue, and Jenkins reporting the use of a deprecated routine, and also cleans up issues reported by groovylint in Visual Studio Code.

There is a follow up #483 that fixes more log noise issues.