Silently ignore empty path elements

resolve_paths function used to print a warning if an input path
was empty. This commit fixes this by explicitly skipping
empty paths during path resolution.

Test: Run adb shell LD_LIBRARY_PATH=: /system/bin/ping
Test: make sure there are no warnings
Bug: http://b/31346121
Change-Id: Ifd79040943dc62fc6e07d9828ff91d1050572809

linker/linker_utils.cpp

@@ -164,6 +164,11 @@ void resolve_paths(std::vector<std::string>& paths,
                    std::vector<std::string>* resolved_paths) {
   resolved_paths->clear();
   for (const auto& path : paths) {
+    // skip empty paths
+    if (path.empty()) {
+      continue;
+    }
+
     char resolved_path[PATH_MAX];
     const char* original_path = path.c_str();
     if (realpath(original_path, resolved_path) != nullptr) {