Fix error not reported if at least one other error expected. (#485)

* fix error not reported if at least one other error expected.

* Fixed unused extern crate error if wasm feature is not enabled.

* No longer reporting deref cycles multiple times.

* Fix filetest type_check.clif.

* Switched comparison order for perf.

* Fixed isa/riscv/verify-encoding.clif filetest.

cranelift/filetests/isa/riscv/verify-encoding.clif

@@ -7,7 +7,7 @@ function %RV32I(i32 link [%x1]) -> i32 link [%x1] {
 ebb0(v9999: i32):
     ; iconst.i32 needs legalizing, so it should throw a
     [R#0,-]         v1 = iconst.i32 0xf0f0f0f0f0 ; error: Instruction failed to re-encode
-    return v9999
+    [Iret#19]       return v9999
 }
 
 function %RV32I(i32 link [%x1]) -> i32 link [%x1] {
@@ -17,5 +17,5 @@ ebb0(v9999: i32):
     v1 = iconst.i32 1
     v2 = iconst.i32 2
     [R#0,-]         v3 = iadd v1, v2 ; error: encoding R#00 should be R#0c
-    return v9999
+    [Iret#19]       return v9999
 }