ignore test cases when checking emscripten

Author: flba-eb

src/test/ui/extern-flag/empty-extern-arg.rs

@@ -1,5 +1,6 @@
 // compile-flags: --extern std=
 // error-pattern: extern location for std does not exist
 // needs-unwind since it affects the error output
+// ignore-emscripten missing eh_catch_typeinfo lang item
 
 fn main() {}

src/test/ui/panic-handler/weak-lang-item.rs

@@ -2,6 +2,7 @@
 // error-pattern: `#[panic_handler]` function required, but not found
 // error-pattern: language item required, but not found: `eh_personality`
 // needs-unwind since it affects the error output
+// ignore-emscripten missing eh_catch_typeinfo lang item
 
 #![no_std]