Make the Ahem font available to test-css and test-wpt tests.

Provide a user stylesheet with an `@font-face` rule for it.

Fix #6195.

Many previously-failing tests now pass, and a few previously-passing now fail.

Among the latter, `font-family-013.htm` and `fonts-013.htm` are testing
that the Ahem font is not used for characters it doesn’t have a glyph for.
They were passing because Ahem was not available at all,
and now fail because we don’t implement font fallback correctly.

The others also use Ahem, but I don’t understand yet what’s going on exactly.

1 files changed, 4 insertions, 0 deletions

diff --git a/resources/ahem.css b/resources/ahem.css
new file mode 100644
index 00000000000..4c7e979e64c
--- /dev/null
+++ b/resources/ahem.css
@@ -0,0 +1,4 @@
+@font-face {
+    font-family: Ahem;
+    src: url(ahem/AHEM____.TTF);
+}