Check for compression lib support before test exec (#4443)

Summary:
Before running CompactFilesTest.SentinelCompressionType, we should check
whether zlib and snappy are supported.

CompactFilesTest.SentinelCompressionType is a newly added test. Compilation and
linking with different options, e.g. COMPILE_WITH_TSAN, COMPILE_WITH_ASAN, etc.
lead to generation of different binaries. On the one hand, it's not clear why
zlib or snappy is present under ASAN, but not under TSAN. On the other hand,
changing the compilation flags for TSAN or ASAN seems a bigger change worth much
more attention. To unblock the cont-runs, I suggest that we simply add these
two checks at the beginning of the test, as we did for
GeneralTableTest.ApproximateOffsetOfCompressed in table/table_test.cc.

Future actions include invesigating the absence of zlib and snappy when
compiling with TSAN, i.e. COMPILE_WITH_TSAN=1, if necessary.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4443

Differential Revision: D10140935

Pulled By: riversand963

fbshipit-source-id: 62f96d1e685386accd2ef0b98f6f754d3fd67b3e

db/compact_files_test.cc

@@ -309,6 +309,14 @@ TEST_F(CompactFilesTest, CompactionFilterWithGetSv) {
 }
 
 TEST_F(CompactFilesTest, SentinelCompressionType) {
+  if (!Zlib_Supported()) {
+    fprintf(stderr, "zlib compression not supported, skip this test\n");
+    return;
+  }
+  if (!Snappy_Supported()) {
+    fprintf(stderr, "snappy compression not supported, skip this test\n");
+    return;
+  }
   // Check that passing `CompressionType::kDisableCompressionOption` to
   // `CompactFiles` causes it to use the column family compression options.
   for (auto compaction_style :