Enable jit disasm in test scripts

Enable jit disasm in test scripts

This change adds a section to the generated bash/cmd scripts for each
test that will run jit-dasm on the test dll when runtests is invoked
with the jitdasm flag.

Also begin updating netci.groovy to support jit-diff scenario.

Other minor fixes:
- Add corefxlab feed for System.CommandLine test dependency

  Without this, restoring the test dependencies retrieved an obsolete
  package of the same name from nuget.org.

- Skip jit-diff job generation for arm

  This fixes an assert that was checking that we are in the default
  scenario on arm.

- Fix an assert in netci.groovy

- Add branch that skips non-checked configurations for jitdiff scenario.

- Fix some dasm failures and a typo in dasm job name

- Some jit-dasm runs were failing because the dependencies in the
  current directory wasn't included in the arguments.

- Escape argument to jit-dasm

- increase timeout for jit-diff job

- Put PR job under a trigger, and some temporary changes for testing

- Make PR trigger look for comment

- Update Newtonsoft.Json version for compatibility with cijobs

- Update cijobs version for retrieving job by commit

- Temporarily run only one test

- Archive raw dasm output instead of zip

- Remove pr-specific logic, enable framework dasm

- Remove windows System.Private.CoreLib.ni.dll from test overlay

  The new test runtime dependencies were placing
  System.Private.CoreLib.ni.dll in the core_root directory, which resulted
  in the native image for windows being placed in the coreoverlay
  directory. We already had similar logic handling this case for
  mscorlib.ni.dll.

  This change also fixes the framework dasm output directory to match the
  test dasm output directory, and fixes some typos in the generated .sh
  files for running dasm on linux.

- Add dasm archiving on non-windows jobs

- Use core_root in bash scripts