ART: Allow to compile interpret-only mips64 files

Include enough infrastructure to allow cross-compiling for mips64,
interpret-only. This includes the instruction-set-features, frame
size info and utils assembler.

Also add a disassembler for oatdump, and support in patchoat.

Note: the runtime cannot run mips64, yet.

Change-Id: Id106581fa76b478984741c62a8a03be0f370d992
diff --git a/runtime/elf_file.cc b/runtime/elf_file.cc
index b6df609..1b91aa6 100644
--- a/runtime/elf_file.cc
+++ b/runtime/elf_file.cc
@@ -1335,6 +1335,8 @@
         if ((GetHeader().e_flags & EF_MIPS_ARCH) == EF_MIPS_ARCH_32R2 ||
             (GetHeader().e_flags & EF_MIPS_ARCH) == EF_MIPS_ARCH_32R6) {
           elf_ISA = kMips;
+        } else if ((GetHeader().e_flags & EF_MIPS_ARCH) == EF_MIPS_ARCH_64R6) {
+          elf_ISA = kMips64;
         }
         break;
       }