[2/n] Migrate per_token_group_quant to torch stable ABI (#36058)

Signed-off-by: Mikayla Gawarecki <mikaylagawarecki@gmail.com>

csrc/libtorch_stable/quantization/w8a8/int8/per_token_group_quant.cu

@@ -0,0 +1,12 @@
+#include <torch/csrc/stable/tensor.h>
+
+#include "libtorch_stable/quantization/w8a8/per_token_group_quant_8bit.h"
+
+void per_token_group_quant_int8(const torch::stable::Tensor& input,
+                                torch::stable::Tensor& output_q,
+                                torch::stable::Tensor& output_s,
+                                int64_t group_size, double eps, double int8_min,
+                                double int8_max) {
+  per_token_group_quant_8bit(input, output_q, output_s, group_size, eps,
+                             int8_min, int8_max);
+}