[sledge] Enable LLVM transformations on test code compiled with -O0

Summary:
By default compiling with `-O0` adds `optnone` annotations, which
prevents the transformations sledge explicitly performs. This diff
adds a flag to disable this uncooperative behavior.

Reviewed By: ngorogiannis

Differential Revision: D27564879

fbshipit-source-id: 061397e3f

sledge/test/Makefile

@@ -4,7 +4,7 @@
 # LICENSE file in the root directory of this source tree.
 
 # additional arguments to pass to clang
-CLANG_ARGS?=-O0
+CLANG_ARGS?=-O0 -Xclang -disable-O0-optnone
 
 # executable to test
 SLEDGE_DBG=$(CURDIR)/../_build/debug/cli/sledge_cli.exe