Temporarily disable unstable tests in memory_test.cc

Summary:
memory_test.cc has some tests that are not unstable but
hard to reproduce, and the cause is the test itself not
the code.  Temporarily disable the tests until
we have a good fix.

Test Plan: memory_test

Reviewers: sdong, anthony, IslamAbdelRahman, rven, kradhakrishnan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D54009

utilities/memory/memory_test.cc

@@ -93,7 +93,7 @@ class MemoryTest : public testing::Test {
   std::vector<uint64_t> usage_history_[MemoryUtil::kNumUsageTypes];
 };
 
-TEST_F(MemoryTest, SharedBlockCacheTotal) {
+TEST_F(MemoryTest, DISABLED_SharedBlockCacheTotal) {
   std::vector<DB*> dbs;
   std::vector<uint64_t> usage_by_type;
   const int kNumDBs = 10;
@@ -144,7 +144,7 @@ TEST_F(MemoryTest, SharedBlockCacheTotal) {
   }
 }
 
-TEST_F(MemoryTest, MemTableAndTableReadersTotal) {
+TEST_F(MemoryTest, DISABLED_MemTableAndTableReadersTotal) {
   std::vector<DB*> dbs;
   std::vector<uint64_t> usage_by_type;
   std::vector<std::vector<ColumnFamilyHandle*>> vec_handles;