Restore curswant settings after indentexpr evaluation

get_expr_indent() attempts to restore cursor position after evaluating
'indentexpr', but the use of :normal commands like:

        normal! w

changes the values of curwin->w_curswant and curwin->w_set_curswant
either through update_curswant(), or directly (like :normal $).

This affects the cursor position when 'nostartofline' is set because the
= command calls beginline() with the BL_SOL flag.
Revert "Merge branch 'update-indentexpr-doc' into guns"

This reverts commit e0b673d9e706dbc237a208219414d5a2ef1867fa, reversing
changes made to 1d9bbe21b74116796b13cd71b255adaac0d515df.
Merge branch 'fix-indentexpr-normal' into guns

* fix-indentexpr-normal:
  Restore curswant settings after indentexpr evaluation