test/run-pass: Add/remove some ignore-win32 flags

Author: klutzy

src/test/run-pass/backtrace.rs

@@ -8,8 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// ignore-win32 FIXME #13259
 // ignore-fast this is executing itself
-#[no_uv];
+#![no_uv]
 
 extern crate native;
 

src/test/run-pass/extern-fn-reachable.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 // ignore-fast
+// ignore-win32 dynamic_lib can read dllexported symbols only
 // ignore-linux apparently dlsym doesn't work on program symbols?
 // ignore-android apparently dlsym doesn't work on program symbols?
 // ignore-freebsd apparently dlsym doesn't work on program symbols?