Move defvars out of eval-when-compile.

Move defvars out of eval-when-compile.
Remove harmful code meant to avoid byte-compiler warnings.
(table-fixed-mode-indicator): Remove.  Use a more complex mode-line
specification that checks table-fixed-width-mode directly.
(table-recognize-region, table-recognize-cell): Use restore-buffer-modified-p.
(table-fixed-width-mode): Remove code that refreshes
table-fixed-mode-indicator.
(*table--cell-describe-bindings, *table--cell-describe-mode):
Avoid obsolete name print-help-return-message.
(table--test-cell-list): Don't use replace-regexp from elisp.
(table--point-entered-cell-function, table--point-left-cell-function):
Don't set table-fixed-mode-indicator, use force-mode-line-update.