Table :width: option ignored by the LaTeX writer.

[gmilde]

Describe the bug

The :width: option for tables was added in release 0.15 (2019-07-20) rsp. commit r8184 (2017-10-06).
The option is defined for all 3 table directives in the specification of Docutils directives:

width : length or percentage of the current line width

Sets the width of the table to the specified length or percentage of the line width. If omitted, the renderer determines the width of the table based on its contents or the column widths.

It is respected in Docutils LaTeX and HTML and in Sphinx HTML output.

How to Reproduce

With the sample input below, both tables should use 50% of the line width.
However, the first table is considerably smaller and the second table 100% wide.

.. table::
   :width: 50%

   =  =
   a  b
   c  d
   =  =


.. table::
   :width: 50%

   =  =
   a  b
   c  d

        quote in cell d
   =  =

Additional context

The issue was detected while discussing the interpretation of percentage length values in LaTeX in #13661.

[gmilde]

The issue is the still un-resolved part of #6564
and related to #3411 (the latter is about column :widths: but touches the topic of a table :width: option).