Suppress valgrind "unimplemented functionality" error

Summary:
Add ROCKSDB_VALGRIND_RUN macro and suppress false-positive "unimplemented functionality" throw by valgrind for steam hints.

Another approach would be add a valgrind suppress file. Valgrind is suppose to print the suppression when given "--gen-suppressions=all" param, which is suppose to be the content for the suppression file. But it doesn't print.
Closes facebook#3174

Differential Revision: D6338786

Pulled By: yiwu-arbug

fbshipit-source-id: 3559efa5f3b92d40d09ad6ac82bc7b59f86c75aa

Makefile

@@ -237,6 +237,11 @@ ifdef COMPILE_WITH_UBSAN
 	PLATFORM_CXXFLAGS += -fsanitize=undefined -DROCKSDB_UBSAN_RUN
 endif
 
+ifdef ROCKSDB_VALGRIND_RUN
+	PLATFORM_CCFLAGS += -DROCKSDB_VALGRIND_RUN
+	PLATFORM_CXXFLAGS += -DROCKSDB_VALGRIND_RUN
+endif
+
 ifndef DISABLE_JEMALLOC
 	ifdef JEMALLOC
 		PLATFORM_CXXFLAGS += -DROCKSDB_JEMALLOC -DJEMALLOC_NO_DEMANGLE
@@ -870,7 +875,7 @@ ubsan_crash_test:
 	$(MAKE) clean
 
 valgrind_test:
-	DISABLE_JEMALLOC=1 $(MAKE) valgrind_check
+	ROCKSDB_VALGRIND_RUN=1 DISABLE_JEMALLOC=1 $(MAKE) valgrind_check
 
 valgrind_check: $(TESTS)
 	$(MAKE) DRIVER="$(VALGRIND_VER) $(VALGRIND_OPTS)" gen_parallel_tests

env/io_posix.cc

@@ -865,13 +865,16 @@ uint64_t PosixWritableFile::GetFileSize() { return filesize_; }
 
 void PosixWritableFile::SetWriteLifeTimeHint(Env::WriteLifeTimeHint hint) {
 #ifdef OS_LINUX
+// Suppress Valgrind "Unimplemented functionality" error.
+#ifndef ROCKSDB_VALGRIND_RUN
   if (hint == write_hint_) {
     return;
   }
   if (fcntl(fd_, F_SET_RW_HINT, &hint) == 0) {
     write_hint_ = hint;
   }
 #endif
+#endif
 }
 
 Status PosixWritableFile::InvalidateCache(size_t offset, size_t length) {