Add tests for previous memory issues

Now that the test suite runs clean with address sanitizer, add some
test cases that previously were used to expose memory errors.

qpdf/qtest/qpdf.test

@@ -222,6 +222,8 @@ my @bug_tests = (
     ["141b", "/W entry size 0", 2],
     ["143", "self-referential ostream", 3],
     ["146", "very deeply nested array", 2],
+    ["147", "previously caused memory error", 2],
+    ["148", "free memory on bad flate", 2],
     ["149", "xref prev pointer loop", 3],
     );
 $n_tests += scalar(@bug_tests);

qpdf/qtest/qpdf/issue-147.out

@@ -0,0 +1,8 @@
+WARNING: issue-147.pdf: can't find PDF header
+WARNING: issue-147.pdf: file is damaged
+WARNING: issue-147.pdf: can't find startxref
+WARNING: issue-147.pdf: Attempting to reconstruct cross-reference table
+WARNING: issue-147.pdf (trailer, file position 9): expected dictionary key but found non-name object; inserting key /QPDFFake1
+WARNING: issue-147.pdf (object 62 0, file position 88): expected endobj
+WARNING: issue-147.pdf (trailer, file position 90): invalid /ID in trailer dictionary
+issue-147.pdf: invalid password

qpdf/qtest/qpdf/issue-147.pdf

@@ -0,0 +1,2 @@
+trailer<<<>/Encrypt 62 0 R>>
+62 0 obj<</Filter/Standard/Length 160/O<>/P 0/R 3/U<>/V 2>>0 0

qpdf/qtest/qpdf/issue-148.out

@@ -0,0 +1,7 @@
+WARNING: issue-148.pdf: can't find PDF header
+WARNING: issue-148.pdf (xref stream: object 8 0, file position 26): stream dictionary lacks /Length key
+WARNING: issue-148.pdf (xref stream: object 8 0, file position 73): attempting to recover stream length
+WARNING: issue-148.pdf (xref stream: object 8 0, file position 73): recovered stream length: 2
+WARNING: issue-148.pdf (xref stream: object 8 0, file position 85): expected endobj
+WARNING: issue-148.pdf (file position 73): error decoding stream data for object 8 0: stream inflate: inflate: data: incorrect header check
+getStreamData called on unfilterable stream