linker: Add unit-test for sleb128_decoder

Add missing test for sleb128_decoder. Also remove
dependency to static library because it exposes malloc/free
which interfere with libc.so malloc/free causing test to crash.

Change-Id: Iedd3268011df9f67ed58c0b58c71f34e30370b23
diff --git a/linker/linker_sleb128.h b/linker/linker_sleb128.h
index a34916f..c4df259 100644
--- a/linker/linker_sleb128.h
+++ b/linker/linker_sleb128.h
@@ -19,6 +19,8 @@
 
 #include <stdint.h>
 
+#include "linker_debug.h"
+
 // Helper classes for decoding LEB128, used in packed relocation data.
 // http://en.wikipedia.org/wiki/LEB128