Add method info to oat files

The method info data is stored separately from the code info to
reduce oat size by improving deduplication of stack maps.

To reduce code size, this moves the invoke info and inline info
method indices to this table.

Oat size for a large app (arm64): 77746816 -> 74023552 (-4.8%)
Average oat size reduction for golem (arm64): 2%

Repurposed unused SrcMapElem deduping to be for MethodInfo.
TODO: Delete SrcMapElem in a follow up CL.

Bug: 36124906

Test: clean-oat-host && test-art-host-run-test

Change-Id: I2241362e728389030b959f42161ce817cf6e2009
diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index b912672..ea463ee 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -341,8 +341,10 @@
     slow_paths_.push_back(std::unique_ptr<SlowPathCode>(slow_path));
   }
 
-  void BuildStackMaps(MemoryRegion region, const DexFile::CodeItem& code_item);
-  size_t ComputeStackMapsSize();
+  void BuildStackMaps(MemoryRegion stack_map_region,
+                      MemoryRegion method_info_region,
+                      const DexFile::CodeItem& code_item);
+  void ComputeStackMapAndMethodInfoSize(size_t* stack_map_size, size_t* method_info_size);
   size_t GetNumberOfJitRoots() const {
     return jit_string_roots_.size() + jit_class_roots_.size();
   }