Revert^2 "JIT: Separate code allocation and initialization."

This reverts commit 63b0c26aae3e7237166dd781eb7a15fbc7c091c2.

Test: ./art/test.py -b -r --host --all-gc -t 708
Reason for revert: Reland after bug fix.
Change-Id: Ic13e2799bf4bdd8ca468f72cc0f3b72f224f2b08
diff --git a/runtime/oat_quick_method_header.h b/runtime/oat_quick_method_header.h
index e41c7ee..9d0883b 100644
--- a/runtime/oat_quick_method_header.h
+++ b/runtime/oat_quick_method_header.h
@@ -50,6 +50,10 @@
     return FromCodePointer(EntryPointToCodePointer(entry_point));
   }
 
+  static size_t InstructionAlignedSize() {
+    return RoundUp(sizeof(OatQuickMethodHeader), GetInstructionSetAlignment(kRuntimeISA));
+  }
+
   OatQuickMethodHeader(const OatQuickMethodHeader&) = default;
   OatQuickMethodHeader& operator=(const OatQuickMethodHeader&) = default;