`L` and `H` commands should move cursor *without* scrolling the editor view

Describe the bug
The L and H commands should only move the cursor, as they do in vim. Currently they both move the cursor and scroll the viewport to make a few lines of context around the cursor visible. Likewise, j should never scroll the viewport up, and k should never scroll it down, which they currently do if the cursor is manually positioned near the top or bottom of the viewport (for example, using the mouse).

LMH are commands for moving the cursor within the current viewport, so it seems logical to me for them to keep the viewport fixed, and to be idempotent, as they are in vim, even though VS Code likes to keep a few lines of context visible when moving the cursor with the arrow keys (but not when moving it with the mouse).

To Reproduce
Steps to reproduce the behavior:

1. Open a file with lots of lines.
2. 500GLk

Expected behavior
Viewport scrolls to have line 500 in the middle. Cursor moves to the bottom visible line without any viewport motion. Cursor moves up one line without any viewport motion.

(From this state, I think I would expect j to scroll the viewport to make a few lines of context visible, since that's how VS Code normally behaves.)

Reproduce 500GLk in a long file, then trace the command handlers for L, H, j, and k. Compare cursor movement with viewport position in the described edge cases; done means L and H leave the viewport fixed, while j and k do not scroll in the prohibited directions.