fix ignore header in MSVC test

Author: lqd

tests/ui/panic-runtime/unwind-tables-target-required.rs

@@ -1,7 +1,7 @@
 // Tests that the compiler errors if the user tries to turn off unwind tables
 // when they are required.
 //
-// only-x86_64-windows-msvc
+// only-x86_64-pc-windows-msvc
 // compile-flags: -C force-unwind-tables=no
 //
 // error-pattern: target requires unwind tables, they cannot be disabled with `-C force-unwind-tables=no`.