Add a16w8 per-op test for var (#19596)

Summary:

Add int16 activation / int8 weight (a16w8) quantization tests for `aten.var` on Ethos-U55 and Ethos-U85.

## Changes
- Add `a16w8_var_test_parameters` dict with 4 test configurations covering keepdim/no-keepdim and correction values 0, 0.5, and 1
- Add `test_var_a16w8_u55_INT` using `EthosU55PipelineINT` with `a16w8_quantization=True, symmetric_io_quantization=True, qtol=128, epsilon=2**-16`
- Add `test_var_a16w8_u85_INT` using `EthosU85PipelineINT` with same kwargs
- Register `ops/test_var.py` in `fbcode/` and `xplat/` `targets.bzl`

bypass-pytorch-oss-checks

Differential Revision: D104532362

Author: christine-long-meta

backends/arm/test/ops/test_var.py

@@ -32,6 +32,11 @@ class Var(torch.nn.Module):
         ),
     }
 
+    test_parameters_ethosu = {
+        "var_4d_keep_dim_0_correction": lambda: (torch.randn(1, 50, 10, 20), True, 0),
+        "var_4d_keep_dim_1_correction": lambda: (torch.randn(1, 30, 15, 20), True, 1),
+    }
+
     def __init__(self, keepdim: bool = True, correction: int = 0):
         super().__init__()
         self.keepdim = keepdim
@@ -170,7 +175,7 @@ def test_var_dim_tosa_INT_no_dim(test_data: Tuple):
     pipeline.run()
 
 
-@common.parametrize("test_data", Var.test_parameters)
+@common.parametrize("test_data", Var.test_parameters_ethosu)
 @common.XfailIfNoCorstone300
 def test_var_dim_u55_INT_no_dim(test_data: Tuple):
     test_data, keepdim, correction = test_data()
@@ -183,7 +188,7 @@ def test_var_dim_u55_INT_no_dim(test_data: Tuple):
     pipeline.run()
 
 
-@common.parametrize("test_data", Var.test_parameters)
+@common.parametrize("test_data", Var.test_parameters_ethosu)
 @common.XfailIfNoCorstone320
 def test_var_dim_u85_INT_no_dim(test_data: Tuple):
     test_data, keepdim, correction = test_data()
@@ -224,6 +229,40 @@ def test_var_dim_vgf_quant_no_dim(test_data: Tuple):
     pipeline.run()
 
 
+@common.parametrize("test_data", Var.test_parameters_ethosu)
+@common.XfailIfNoCorstone300
+def test_var_a16w8_u55_INT(test_data: Tuple):
+    test_data, keepdim, correction = test_data()
+    pipeline = EthosU55PipelineINT[input_t1](
+        Var(keepdim, correction),
+        (test_data,),
+        aten_ops=[],
+        exir_ops=[],
+        a16w8_quantization=True,
+        symmetric_io_quantization=True,
+        qtol=128,
+        epsilon=2**-16,
+    )
+    pipeline.run()
+
+
+@common.parametrize("test_data", Var.test_parameters_ethosu)
+@common.XfailIfNoCorstone320
+def test_var_a16w8_u85_INT(test_data: Tuple):
+    test_data, keepdim, correction = test_data()
+    pipeline = EthosU85PipelineINT[input_t1](
+        Var(keepdim, correction),
+        (test_data,),
+        aten_ops=[],
+        exir_ops=[],
+        a16w8_quantization=True,
+        symmetric_io_quantization=True,
+        qtol=128,
+        epsilon=2**-16,
+    )
+    pipeline.run()
+
+
 #############
 ## VarDim ###
 #############

backends/arm/test/targets.bzl

@@ -39,6 +39,7 @@ def define_arm_tests():
         "ops/test_exp.py",
         "ops/test_reciprocal.py",
         "ops/test_mean_dim.py",
+        "ops/test_var.py",
     ]
 
     # Quantization