Allow breaking line after space with white-space: break-spaces (#33376)

`white-space: break-spaces` should allow a soft wrap opportunity *after*
every preserved white space. Then, to avoid breaking before the first
white space, `TextRunSegment::shape_text()` has some logic to separate
it from the following spaces and put it with the preceding text instead.

The problem was that, when combined with `word-break: keep-all`, we were
then only checking whether there were more white spaces afterwards,
ignoring the soft wrap opportunity after the first one.

Also removing a duplicated `can_break_anywhere` variable.

Signed-off-by: Oriol Brufau <obrufau@igalia.com>

tests/wpt/meta/MANIFEST.json

@@ -254546,6 +254546,19 @@
         {}
        ]
       ],
+      "break-spaces-with-word-break-001.html": [
+       "ee31fd627130eeb40fd22d0b9bc4fa6e9eb3aca7",
+       [
+        null,
+        [
+         [
+          "/css/reference/ref-filled-green-100px-square.xht",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
       "control-chars-000.html": [
        "b038fe9a90d3b8b9cb3bde7fd46396c7121688c9",
        [