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/arch/instruction_set_features.h b/runtime/arch/instruction_set_features.h
index 2c6e699..e4513ef 100644
--- a/runtime/arch/instruction_set_features.h
+++ b/runtime/arch/instruction_set_features.h
@@ -28,6 +28,7 @@
 class ArmInstructionSetFeatures;
 class Arm64InstructionSetFeatures;
 class MipsInstructionSetFeatures;
+class Mips64InstructionSetFeatures;
 class X86InstructionSetFeatures;
 class X86_64InstructionSetFeatures;
 
@@ -87,6 +88,9 @@
   // Down cast this MipsInstructionFeatures.
   const MipsInstructionSetFeatures* AsMipsInstructionSetFeatures() const;
 
+  // Down cast this Mips64InstructionFeatures.
+  const Mips64InstructionSetFeatures* AsMips64InstructionSetFeatures() const;
+
   // Down cast this X86InstructionFeatures.
   const X86InstructionSetFeatures* AsX86InstructionSetFeatures() const;