JIT baseline: trigger optimized compilation on hotness threshold.

- Add a new hotness count in the ProfilingInfo to not conflict with
interpreter hotness which may use it for OSR.
- Add a baseline flag in the OatQuickMethodHeader to identify baseline
compiled methods.
- Add a -Xusetieredjit flag to experiment and test.

Bug: 119800099
Test: test.py with Xusetieredjit to true

Change-Id: I8512853f869f1312e3edc60bf64413dee9143c52
diff --git a/compiler/optimizing/code_generator_x86.h b/compiler/optimizing/code_generator_x86.h
index e305b50..16446ce 100644
--- a/compiler/optimizing/code_generator_x86.h
+++ b/compiler/optimizing/code_generator_x86.h
@@ -625,6 +625,7 @@
   void GenerateExplicitNullCheck(HNullCheck* instruction) override;
 
   void MaybeGenerateInlineCacheCheck(HInstruction* instruction, Register klass);
+  void MaybeIncrementHotness(bool is_frame_entry);
 
   // When we don't know the proper offset for the value, we use kDummy32BitOffset.
   // The correct value will be inserted when processing Assembler fixups.