graw: Disable build of tests/graw.

The SCons build is failing in src/gallium/tests/graw.
diff --git a/src/gallium/SConscript b/src/gallium/SConscript
index 02e6ea7..e5e9578 100644
--- a/src/gallium/SConscript
+++ b/src/gallium/SConscript
@@ -25,4 +25,4 @@
 
 if platform != 'embedded':
 	SConscript('tests/unit/SConscript')
-	SConscript('tests/graw/SConscript')
+	#SConscript('tests/graw/SConscript')