fix local float8 tests on H100 (#1438)

Summary:

float8 tests were failing my machine. I bisected the failure to
#1344. Further investigation found
that that PR was fine, but the tolerance for one of the tests was too
tight, adding a test changed the random seed of the data, and things
started failing.

Switching to SQNR for a more robust measurement.

Test Plan: CI

Reviewers:

Subscribers:

Tasks:

Tags:

test/float8/test_base.py

@@ -730,14 +730,10 @@ def test_pad_inner_dim(self, base_dtype, use_fast_accum):
             emulated_config,
             GemmInputRole.WEIGHT,
         )
-        out_emualted = a_fp8 @ b_fp8
-        out_emualted.to(compare_type)
-
-        if base_dtype in {torch.bfloat16, torch.float16}:
-            atol, rtol = 7e-2, 7e-2
-        else:
-            atol, rtol = 2e-3, 2e-3
-        torch.testing.assert_close(out_padded, out_emualted, atol=atol, rtol=rtol)
+        out_emulated = a_fp8 @ b_fp8
+        out_emulated.to(compare_type)
+        sqnr = compute_error(out_padded, out_emulated)
+        assert sqnr > 50.0
 
 
 class TestNumerics: