[tint][ir] Fix unit test expected output

Change-Id: I9fa781982719aff4737cf50c4915eb5240988ded
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/189783
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>
diff --git a/src/tint/lang/core/ir/validator_test.cc b/src/tint/lang/core/ir/validator_test.cc
index a73a3c5..9d5b0f1 100644
--- a/src/tint/lang/core/ir/validator_test.cc
+++ b/src/tint/lang/core/ir/validator_test.cc
@@ -250,7 +250,7 @@
     EXPECT_EQ(res.Failure().reason.Str(),
               R"(:1:17 error: function parameter has nullptr type
 %my_func = func(%my_param:undef):void {
-                ^^^^^^^^^^^^^^^^^
+                ^^^^^^^^^^^^^^^
 
 note: # Disassembly
 %my_func = func(%my_param:undef):void {