Let's sprinkle some FastJNI into Parcel.

Before:

    benchmark   ns linear runtime
     ReadByte  918 ===========================
      ReadInt  877 ==========================
     ReadLong  880 ==========================
    WriteByte 1002 ==============================
     WriteInt  945 ============================
    WriteLong  957 ============================
    vm: app_process

After:

    benchmark  ns linear runtime
     ReadByte 824 ===========================
      ReadInt 780 =========================
     ReadLong 780 =========================
    WriteByte 895 =============================
     WriteInt 907 ==============================
    WriteLong 851 ============================
    vm: app_process

Change-Id: I746fe8ea3607e29d86007bd144339c84b063c360