Add embedder test for stream length beyond end of file.

testing/resources/bug_57.pdf

Index: testing/resources/bug_57.pdf
diff --git a/testing/resources/bug_57.pdf b/testing/resources/bug_57.pdf
new file mode 100644
index 0000000000000000000000000000000000000000..d954c43f54f11d849b98694cb4768b79acd06104
--- /dev/null
+++ b/testing/resources/bug_57.pdf
@@ -0,0 +1,57 @@
+%PDF-1.7
+% ò¤ô
+1 0 obj <<
+  /Type /Catalog
+  /Pages 2 0 R
+>>
+2 0 obj <<
+  /Type /Pages
+  /MediaBox [ 0 0 200 200 ]
+  /Count 1
+  /Kids [ 3 0 R ]
+>>
+endobj
+3 0 obj <<
+  /Type /Page
+  /Parent 2 0 R
+  /Resources <<
+    /Font <<
+      /F1 4 0 R
+    >>
+  >>
+  /Contents 5 0 R
+>>
+endobj
+4 0 obj <<
+  /Type /Font
+  /Subtype /Type1
+  /BaseFont /Times-Roman
+>>
+endobj
+% page content with streamlength past end-of-file.
+5 0 obj <<
+  /Length 9999
+>>
+stream
+BT
+70 50 TD
+/F1 12 Tf
+(Hello, world!) Tj
+ET
+endstream
+endobj
+xref
+0 6
+0000000000 65536 f
+0000000015 00000 n
+0000000061 00000 n
+0000000154 00000 n
+0000000280 00000 n
+0000000409 00000 n
+trailer <<
+  /Size 6
+  /Root 1 0 R
+>>
+startxref
+506
+%%EOF