New test of explicit deref operator.

src/Makefile

@@ -356,6 +356,7 @@ TEST_XFAILS_LLVM := $(addprefix test/run-pass/, \
                       complex.rs \
                       dead-code-one-arm-if.rs \
                       deep.rs \
+                      deref.rs \
                       div-mod.rs \
                       drop-on-ret.rs \
                       else-if.rs \

src/test/run-pass/deref.rs

@@ -0,0 +1,4 @@
+fn main() {
+   let @int x = @10;
+   let int y = *x;
+}