Disable AHB support for now

This is incomplete. Advertising it causes various things to try and use it, including parts of CTS.

Bug: b/151813470
Change-Id: Ic4643bd2d3065effd4bddac6320d65c336ee6494
diff --git a/src/Android.bp b/src/Android.bp
index 2f8683a..ef43929 100644
--- a/src/Android.bp
+++ b/src/Android.bp
@@ -616,7 +616,7 @@
 
     cflags: [
         "-DLOG_TAG=\"swiftshader\"",
-        "-DSWIFTSHADER_EXTERNAL_MEMORY_ANDROID_HARDWARE_BUFFER",
+        //"-DSWIFTSHADER_EXTERNAL_MEMORY_ANDROID_HARDWARE_BUFFER",
         "-DSWIFTSHADER_ENABLE_ASTC",  // TODO(b/150130101)
     ],