test: Remove Windows LTO workaround that is no longer needed.

Author: alexrp

test/standalone/c_compiler/build.zig

@@ -41,10 +41,6 @@ fn add(
     b.default_step.dependOn(&exe_cpp.step);
 
     switch (target.result.os.tag) {
-        .windows => {
-            // https://github.com/ziglang/zig/issues/8531
-            exe_cpp.want_lto = false;
-        },
         .macos => {
             // https://github.com/ziglang/zig/issues/8680
             exe_cpp.want_lto = false;