Fix uninitialization of shiftedRt2

[VourMa]

As per title, following up on cms-sw#46802 (comment).

Also cleaned up a few comments.

[slava77]

/run all

[github-actions]

The PR was built and ran successfully in standalone mode. Here are some of the comparison plots.

The full set of validation and comparison plots can be found here.

Here is a timing comparison:

   Evt    Hits       MD       LS      T3       T5       pLS       pT5      pT3      TC       Reset    Event     Short             Rate
   avg     41.2    387.6    194.7    131.7    137.3    500.8    119.7    246.2    102.7      3.5    1865.5    1323.5+/- 371.6     497.1   explicit[s=4] (target branch)
   avg     40.8    392.0    193.9    130.6    138.0    503.5    119.7    251.1    102.4      3.1    1875.1    1330.7+/- 369.0     497.1   explicit[s=4] (this PR)

[github-actions]

The PR was built and ran successfully with CMSSW. Here are some plots.

OOTB All Tracks

The full set of validation and comparison plots can be found here.