Move caret to correct position when dir=auto

LayoutTests/editing/caret/caret-direction-auto-expected.txt

+Tests various scenarios for caret position when direction is auto
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS textarea.value is "א!"
+1. Caret is at right if text is in LTR direction
+PASS textarea.value is "א!\nhello"
+Compares lines if they are different
+PASS beforeCaretPos[1] is not afterCaretPos[1]
+New text is in LTR direction, start of caret will differ
+PASS beforeCaretPos[0] is > afterCaretPos[0]
+2. Addition of RTL text in middle of LTR text, caret moves to the left of the line.
+PASS textarea.value is "א!\nhelloאא"
+RTL text added will be move caret to start of position where hello begins
+PASS beforeCaretPos[0] is afterCaretPos[0]+afterCaretPos[2]
+3. Adding LTR text after RTL should move caret towards right.
+PASS textarea.value is "א!\nhelloאאbye"
+Start position of caret is same
+PASS beforeCaretPos[0]+beforeCaretPos[2] is afterCaretPos[0]
+But end position differs
+PASS beforeCaretPos[0]+beforeCaretPos[2] is not afterCaretPos[0]+afterCaretPos[2]
+4. Adding space, caret should move caret
+PASS textarea.value is "א!\nhelloאאbye "
+PASS afterCaretPos[0]+afterCaretPos[2] is > beforeCaretPos[0]+beforeCaretPos[2]
+PASS successfullyParsed is true
+
+TEST COMPLETE
+