behavior tests: correction of C pointer test

This test was also covering this behavior:

```zig
test "equality of pointers to comptime const" {
    const a: i32 = undefined;
    comptime assert(&a == &a);
}
```

This check belongs in its own behavior test which isolates this
behavior; not bundled along with a C pointer test.

1 files changed, 6 insertions, 2 deletions

diff --git a/test/behavior/pointers.zig b/test/behavior/pointers.zig
index 5b9c3c8cf0..42939986d4 100644
--- a/test/behavior/pointers.zig
+++ b/test/behavior/pointers.zig
@@ -214,7 +214,10 @@ test "allowzero pointer and slice" {
 }
 
 test "assign null directly to C pointer and test null equality" {
-    if (builtin.zig_backend != .stage1) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
 
     var x: [*c]i32 = null;
     try expect(x == null);
@@ -238,7 +241,8 @@ test "assign null directly to C pointer and test null equality" {
         @panic("fail");
     }
     const othery: i32 = undefined;
-    comptime try expect((y orelse &othery) == &othery);
+    const ptr_othery = &othery;
+    comptime try expect((y orelse ptr_othery) == ptr_othery);
 
     var n: i32 = 1234;
     var x1: [*c]i32 = &n;