Revert "Revert "Fast ART x86 interpreter""

This reverts commit 2d093a1213cc2f85b5e5e02782332657c479eb94.

Disable x86 mterp compilation on Mac host builds (but keep enabled
for all target builds).

Change-Id: Ie355279f166d2964a786646ee53f065b7e0f5ede
diff --git a/runtime/interpreter/mterp/x86/op_const.S b/runtime/interpreter/mterp/x86/op_const.S
new file mode 100644
index 0000000..dc69530
--- /dev/null
+++ b/runtime/interpreter/mterp/x86/op_const.S
@@ -0,0 +1,4 @@
+    /* const vAA, #+BBBBbbbb */
+    movl    2(rPC), %eax                    # grab all 32 bits at once
+    SET_VREG %eax rINST                     # vAA<- eax
+    ADVANCE_PC_FETCH_AND_GOTO_NEXT 3