Replace stringstream with std::cout and std::cerr am: 97abf1512c

Original change: https://android-review.googlesource.com/c/platform/system/memory/libmeminfo/+/2249886

Change-Id: Ife3cc0a5c9e620421cebad171bf72a8edb3af402
Signed-off-by: Automerger Merge Worker <[email protected]>