Fix overflow testing in sbrk. am: 1944780b am: 3a5ebf31 -s ours am: d95336ac am: 09933196 am: 0ae30d9a am: 83b0671a am: 10a48fb5 am: fd84d78b am: b4d92e13 am: ad80daaa am: 7189a4cc am: d120719e * commit 'd120719e': Fix overflow testing in sbrk. Change-Id: I4ab3da189f46d29b1e9fcd9737227e4fcf73221e