Issue 484651: vertical writing modes (vlr and vrl) use wrong arrow navigation keyboard for caret movement within contenteditable block of text

Steps to reproduce and correspondent expected results (mongolian only)

  1. Mouse-click into the contenteditable div below
  2. press left arrow key in the keyboard should (expected) move blinking caret toward left
  3. press right arrow key in the keyboard should (expected) move blinking caret toward right
  4. press up arrow key in the keyboard should (expected) move blinking caret up
  5. press down arrow key in the keyboard should (expected) move blinking caret down
  6. when blinking caret at top, pressing the up arrow key should (expected) move it to previous (left) line
  7. when blinking caret at bottom, pressing the down arrow key should (expected) move it to next (right) line
ᠺᠣᠮᠫᠢᠦ᠋ᠲ᠋ᠧᠷ ᠪᠣᠯ ᠴᠣ᠋ ᠰᠢᠨ᠎ᠡ ᠪᠣᠲᠤᠯᠭ᠎ᠠ ᠶᠢᠨ ᠮᠠᠰᠢᠨ ᠮᠦᠨ᠃ ᠲᠡᠷᠡ ᠨᠢ ᠬᠦᠮᠦᠨ ᠦ ᠳᠠᠷᠢᠬᠢᠨ ᠤ ᠠᠵᠢᠯᠯᠠᠭ᠎ᠠ ᠶᠢ ᠳᠠᠭᠤᠷᠢᠶᠠᠵᠤ ᠲᠥᠯᠦᠪᠯᠡᠨ ᠭᠠᠷᠭᠠᠭᠰᠠᠨ ᠨᠢᠭᠡ ᠵᠦᠢᠯ ᠦᠨ ᠡᠯᠧᠺᠲ᠋ᠷᠦᠨ ᠪᠠᠭᠠᠵᠢ ᠪᠣᠯᠣᠨ᠎ᠠ᠃ ᠺᠣᠮᠫᠢᠦ᠋ᠲ᠋ᠧᠷ ᠬᠦᠮᠦᠨ ᠦ ᠳᠠᠷᠢᠬᠢ ᠲᠠᠢ ᠠᠳᠠᠯᠢ ᠪᠡᠷ ᠰᠤᠷᠠᠭ ᠳᠣᠬᠢᠶ᠎ᠠ ᠶᠢ ᠬᠠᠳᠠᠭᠠᠯᠠᠵᠤ ᠴᠢᠳᠠᠬᠤ ᠪᠡᠷ ᠪᠠᠷᠠᠬᠤ ᠦᠭᠡᠢ᠂ ᠪᠠᠰᠠ ᠬᠠᠳᠠᠭᠠᠯᠠᠭᠳᠠᠵᠤ ᠪᠠᠢᠭ᠎ᠠ ᠰᠤᠷᠠᠭ ᠳᠣᠬᠢᠶᠠᠨ ᠳᠤ ᠵᠣᠬᠢᠬᠤ ᠬᠡᠮᠵᠢᠶᠡᠨ ᠤ ᠯᠣᠭᠢᠭ ᠵᠦᠢᠴᠢᠯᠡᠯ ᠦᠨ ᠠᠵᠢᠯᠯᠠᠭ᠎ᠠ ᠪᠠ ᠮᠠᠭᠠᠳᠯᠠᠯᠲᠠ ᠦᠭᠴᠦ ᠴᠢᠳᠠᠨ᠎ᠠ᠃ ᠺᠣᠮᠫᠢᠦ᠋ᠲ᠋ᠧᠷ ᠬᠦᠮᠦᠨ ᠦ ᠳᠠᠷᠢᠬᠢ ᠲᠠᠢ ᠠᠳᠠᠯᠢ ᠪᠡᠷ ᠰᠤᠷᠠᠭ ᠳᠣᠬᠢᠶ᠎ᠠ ᠶᠢ ᠬᠠᠳᠠᠭᠠᠯᠠᠵᠤ ᠴᠢᠳᠠᠬᠤ ᠪᠡᠷ ᠪᠠᠷᠠᠬᠤ ᠦᠭᠡᠢ᠂ ᠪᠠᠰᠠ ᠬᠠᠳᠠᠭᠠᠯᠠᠭᠳᠠᠵᠤ ᠪᠠᠢᠭ᠎ᠠ ᠰᠤᠷᠠᠭ ᠳᠣᠬᠢᠶᠠᠨ ᠳᠤ ᠵᠣᠬᠢᠬᠤ ᠬᠡᠮᠵᠢᠶᠡᠨ ᠤ ᠯᠣᠭᠢᠭ ᠵᠦᠢᠴᠢᠯᠡᠯ ᠦᠨ ᠠᠵᠢᠯᠯᠠᠭ᠎ᠠ ᠪᠠ ᠮᠠᠭᠠᠳᠯᠠᠯᠲᠠ ᠦᠭᠴᠦ ᠴᠢᠳᠠᠨ᠎ᠠ᠃
すべての人間は、生まれながらにして自由であり、かつ、尊厳と権利と について平等である。人間は、理性と良心とを授けられており、互いに同 胞の精神をもって行動しなければならない。