Delete ArtMethod gc_map_ field

Moved the gc_map field from OatMethod to OatQuickMethodHeader.
Deleted the ArtMethod gc_map_ field.

Bug: 17643507

Change-Id: Ifa0470c3e4c2f8a319744464d94c6838b76b3d48

(cherry picked from commit 807140048f82a2b87ee5bcf337f23b6a3d1d5269)
diff --git a/runtime/oat_file.cc b/runtime/oat_file.cc
index 54f5eab..91e571b 100644
--- a/runtime/oat_file.cc
+++ b/runtime/oat_file.cc
@@ -577,18 +577,15 @@
 const OatFile::OatMethod OatFile::OatClass::GetOatMethod(uint32_t method_index) const {
   const OatMethodOffsets* oat_method_offsets = GetOatMethodOffsets(method_index);
   if (oat_method_offsets == nullptr) {
-    return OatMethod(nullptr, 0, 0);
+    return OatMethod(nullptr, 0);
   }
   if (oat_file_->IsExecutable() ||
       Runtime::Current() == nullptr ||        // This case applies for oatdump.
       Runtime::Current()->IsCompiler()) {
-    return OatMethod(
-        oat_file_->Begin(),
-        oat_method_offsets->code_offset_,
-        oat_method_offsets->gc_map_offset_);
+    return OatMethod(oat_file_->Begin(), oat_method_offsets->code_offset_);
   } else {
     // We aren't allowed to use the compiled code. We just force it down the interpreted version.
-    return OatMethod(oat_file_->Begin(), 0, 0);
+    return OatMethod(oat_file_->Begin(), 0);
   }
 }
 
@@ -596,7 +593,6 @@
   CHECK(method != NULL);
   method->SetEntryPointFromPortableCompiledCode(GetPortableCode());
   method->SetEntryPointFromQuickCompiledCode(GetQuickCode());
-  method->SetNativeGcMap(GetNativeGcMap());  // Used by native methods in work around JNI mode.
 }
 
 bool OatFile::IsPic() const {