Propagate InstructionSetFeatures to ElfBuilder.

This is subset of CL171665 and it separates it into two.
It will be needed to generate .MIPS.abiflags ELF section.

Change-Id: I5557e7cb98d0fa1dc57c85cf6161e119c6d50a1a
diff --git a/oatdump/oatdump.cc b/oatdump/oatdump.cc
index c187536..b52f30e 100644
--- a/oatdump/oatdump.cc
+++ b/oatdump/oatdump.cc
@@ -115,11 +115,13 @@
 
   bool Symbolize() {
     const InstructionSet isa = oat_file_->GetOatHeader().GetInstructionSet();
+    const InstructionSetFeatures* features = InstructionSetFeatures::FromBitmap(
+        isa, oat_file_->GetOatHeader().GetInstructionSetFeaturesBitmap());
 
     File* elf_file = OS::CreateEmptyFile(output_name_.c_str());
     std::unique_ptr<BufferedOutputStream> output_stream(
         MakeUnique<BufferedOutputStream>(MakeUnique<FileOutputStream>(elf_file)));
-    builder_.reset(new ElfBuilder<ElfTypes32>(isa, output_stream.get()));
+    builder_.reset(new ElfBuilder<ElfTypes32>(isa, features, output_stream.get()));
 
     builder_->Start();