Make patchoat match offset when given a patched image

Previously if we gave patchoat a patched image and a already patched
(but improperly relocated) oat file it would not correctly patch the
oat file to the same offset as the image.

Bug: 22599792
Bug: 23119724
Change-Id: I8773022bd75c2e0b7eb529893b147cbd8792bcad
diff --git a/runtime/elf_file.h b/runtime/elf_file.h
index 48cb4b8..1188c97 100644
--- a/runtime/elf_file.h
+++ b/runtime/elf_file.h
@@ -60,7 +60,7 @@
 
   const File& GetFile() const;
 
-  bool GetSectionOffsetAndSize(const char* section_name, uint64_t* offset, uint64_t* size);
+  bool GetSectionOffsetAndSize(const char* section_name, uint64_t* offset, uint64_t* size) const;
 
   uint64_t FindSymbolAddress(unsigned section_type,
                              const std::string& symbol_name,