Auto merge of #13681 - gpoesia:master, r=mbrubeck

Fix margin size calculation for TableWrapper

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Fixes inline size calculation for TableWrapper. The table's width was always reaching the inline size equation solver as a specified variable, which was causing the system to be overdetermined when there was a margin specified for the table, and this caused the overflow reported in #12748. The fix consists in handling three cases when the table's width is not specified: if the preferred size of all columns fits, it is returned; if the minimum size does not fit, it is returned instead (it will overflow), otherwise, it is returned as a free variable (that should be solved together with the margin to some value above the minimum width and below the preferred width).

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #12748
- [X] There are tests for these changes

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components/layout/table_wrapper.rs

@@ -766,7 +766,13 @@ fn initial_computed_inline_size(block: &mut BlockFlow,
                                                        containing_block_inline_size);
     match inline_size_from_style {
         MaybeAuto::Auto => {
-            MaybeAuto::Specified(min(containing_block_inline_size, preferred_width_of_all_columns))
+            if preferred_width_of_all_columns + table_border_padding <= containing_block_inline_size {
+                MaybeAuto::Specified(preferred_width_of_all_columns + table_border_padding)
+            } else if minimum_width_of_all_columns > containing_block_inline_size {
+                MaybeAuto::Specified(minimum_width_of_all_columns)
+            } else {
+                MaybeAuto::Auto
+            }
         }
         MaybeAuto::Specified(inline_size_from_style) => {
             MaybeAuto::Specified(max(inline_size_from_style - table_border_padding,