target: x86_64 backend can build compiler rt with coff

Without allowing this, the references to `compiler_rt.dll` emitted by
the coff linker will prevent the executable from running.

Author: jacobly0

src/target.zig

@@ -375,11 +375,7 @@ pub fn canBuildLibCompilerRt(target: *const std.Target) enum { no, yes, llvm_onl
         else => {},
     }
     return switch (zigBackend(target, false)) {
-        .stage2_aarch64 => .yes,
-        .stage2_x86_64 => switch (target.ofmt) {
-            .elf, .macho => .yes,
-            else => .llvm_only,
-        },
+        .stage2_aarch64, .stage2_x86_64 => .yes,
         else => .llvm_only,
     };
 }