Revert^4 "Compiler changes for bitstring based type checks."

Disabled the build time flag. (No image version bump needed.)

Bug: 26687569
Bug: 64692057
Bug: 76420366

This reverts commit 3fbd3ad99fad077e5c760e7238bcd55b07d4c06e.

Change-Id: I5d83c4ce8a7331c435d5155ac6e0ce1c77d60004
diff --git a/compiler/optimizing/optimizing_compiler_stats.h b/compiler/optimizing/optimizing_compiler_stats.h
index 00194ff..e0a9cfb 100644
--- a/compiler/optimizing/optimizing_compiler_stats.h
+++ b/compiler/optimizing/optimizing_compiler_stats.h
@@ -99,6 +99,7 @@
   kConstructorFenceRemovedLSE,
   kConstructorFenceRemovedPFRA,
   kConstructorFenceRemovedCFRE,
+  kBitstringTypeCheck,
   kJitOutOfMemoryForCommit,
   kLastStat
 };