Add another variant of the PrependInteger UMR stack.

base/data/purify/base_unittests.exe_UMR_flakey.txt

Index: base/data/purify/base_unittests.exe_UMR_flakey.txt
diff --git a/base/data/purify/base_unittests.exe_UMR_flakey.txt b/base/data/purify/base_unittests.exe_UMR_flakey.txt
index d4c7acf70f53a837a1aed602db1053d58cc14c86..443fb23a5a363b40a6708f1604d141d254270a16 100644
--- a/base/data/purify/base_unittests.exe_UMR_flakey.txt
+++ b/base/data/purify/base_unittests.exe_UMR_flakey.txt
@@ -26,3 +26,23 @@ Alloc Location
    base/crypto/rsa_private_key.cc  base::PrivateKeyInfoCodec::Export(vector::std *)
    base/crypto/rsa_private_key_win.cc  base::RSAPrivateKey::ExportPrivateKey(vector::std *)
    ...
+
+Uninitialized memory read in base::PrivateKeyInfoCodec::PrependIntegerImpl(BYTE *,int,list<BYTE,allocator<BYTE>::std>::std *,bool)
+Error Location
+   base/crypto/rsa_private_key.cc  base::PrivateKeyInfoCodec::PrependIntegerImpl(BYTE *,int,list::std *,bool)
+   base/crypto/rsa_private_key.cc  base::PrivateKeyInfoCodec::PrependInteger(vector::std const&,list::std *)
+   base/crypto/rsa_private_key.cc  base::PrivateKeyInfoCodec::Export(vector::std *)
+   base/crypto/rsa_private_key_win.cc  base::RSAPrivateKey::ExportPrivateKey(vector::std *)
+   base/crypto/signature_creator_unittest.cc  SignatureCreatorTest_BasicTest_Test::TestBody(void)
+   testing/gtest/src/gtest.cc  testing::Test::Run(void)
+   ^^^  
+Alloc Location
+   ...  
+   base/crypto/rsa_private_key.cc  base::PrivateKeyInfoCodec::PrependIntegerImpl(BYTE *,int,list::std *,bool)
+   base/crypto/rsa_private_key.cc  base::PrivateKeyInfoCodec::PrependInteger(vector::std const&,list::std *)
+   base/crypto/rsa_private_key.cc  base::PrivateKeyInfoCodec::Export(vector::std *)
+   base/crypto/rsa_private_key_win.cc  base::RSAPrivateKey::ExportPrivateKey(vector::std *)
+   base/crypto/signature_creator_unittest.cc  SignatureCreatorTest_BasicTest_Test::TestBody(void)
+   testing/gtest/src/gtest.cc  testing::Test::Run(void)
+   ^^^  
+