fix ISLE,Pos'col, looks like a bug to me. (#6041)

* fix col

* fix test failure

cranelift/isle/isle/src/lexer.rs

@@ -137,7 +137,7 @@ impl<'a> Lexer<'a> {
             file: self.pos.file,
             offset: self.pos.offset - self.file_starts[self.pos.file],
             line: self.pos.line,
-            col: self.pos.file,
+            col: self.pos.col,
         }
     }
 

cranelift/isle/isle/src/sema.rs

@@ -2479,7 +2479,7 @@ mod test {
                     file: 0,
                     offset: 19,
                     line: 2,
-                    col: 0,
+                    col: 18,
                 },
             ),
             Type::Enum {
@@ -2520,7 +2520,7 @@ mod test {
                     file: 0,
                     offset: 58,
                     line: 3,
-                    col: 0,
+                    col: 18,
                 },
             },
         ];