[librsvg] Add testcase for recent fix

[Benjamin Otte <otte src gnome org>]

commit 5cb7fb4b2dc5561047e26718151a25c841f5e2cd
Author: Benjamin Otte <otte redhat com>
Date:   Thu Nov 5 23:01:56 2015 +0100

    Add testcase for recent fix
    
    This adds a testcase for the fix in commit
    1d9e887d42ccd3077a3a867815a5733e91b654bb
    
    https://bugzilla.gnome.org/show_bug.cgi?id=757286

 tests/fixtures/reftests/nonexisting-filter-ref.png |  Bin 0 -> 155 bytes
 tests/fixtures/reftests/nonexisting-filter.svg     |    3 +++
 2 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/tests/fixtures/reftests/nonexisting-filter-ref.png 
b/tests/fixtures/reftests/nonexisting-filter-ref.png
new file mode 100644
index 0000000..d724b8f
Binary files /dev/null and b/tests/fixtures/reftests/nonexisting-filter-ref.png differ
diff --git a/tests/fixtures/reftests/nonexisting-filter.svg b/tests/fixtures/reftests/nonexisting-filter.svg
new file mode 100644
index 0000000..5fb9927
--- /dev/null
+++ b/tests/fixtures/reftests/nonexisting-filter.svg
@@ -0,0 +1,3 @@
+<svg xmlns="http://www.w3.org/2000/svg"; width="10px" height="10px">
+  <rect fill="red" width="10" height="10" filter="url(#doesnotexit)"/>
+</svg>