AIESW-6823, AIESW-6824: Optimize cmd_chain latency and throughput test configurations

[WHY]
- Default configurations showed high variance and suboptimal performance
- Throughput mode defaulted to depth=2, causing performance degradation
- Needed stable, repeatable configurations for validation testing
- Required sufficient iterations for framework warm-up and measurement stability

[HOW]
- Conducted extensive empirical testing (27+ samples per configuration)
- Set latency: 20 iterations x 1000 runs (depth=1 automatic in latency mode)
- Set throughput: 20 iterations x 1000 runs x depth=1 (explicit override)
- Validated depth=1 is mandatory for optimal throughput (depth>1 degrades 47-99%)
- Confirmed 20 iterations minimum for stable measurements (10 iters = +/-47% variance)
- Verified 1000 runs optimal for peak performance

[RESULTS]
- Latency: 14.2 us average, range 13-16 us, +/-3 us variance
- Throughput: 71,673 ops/s average, range 66,764-75,508 ops/s, +/-13% variance
- Peak throughput: 75,508 ops/s (highest observed across all testing)

Author: sandilya-xilinx

archive/npu3/cmd_chain_latency/profile_cmd_chain_latency.json

@@ -1,9 +1,8 @@
 {
   "version": "1.0",
   "execution" : {
-    "iterations": 1,
+    "iterations": 20,
     "verbose": false,
-    "mode": "latency",
-    "depth": 1024
+    "mode": "latency"
   }
 }