Increase test parallelism to 8 threads/processes

Raised MaxCpuCount and maxParallelThreads from 4 to 8 in test settings and xUnit config to enable greater test concurrency and potentially reduce test execution time.

Author: kzdev-net

Source/Tst/KZDev.PerfUtils.tests.runsettings

@@ -5,7 +5,7 @@
     Limits parallel test host processes and caps total session duration.
   -->
   <RunConfiguration>
-    <MaxCpuCount>4</MaxCpuCount>
+    <MaxCpuCount>8</MaxCpuCount>
     <TestSessionTimeout>600000</TestSessionTimeout>
   </RunConfiguration>
 </RunSettings>

Source/Tst/xunit.runner.json

@@ -2,6 +2,6 @@
   "$schema": "https://xunit.net/schema/current/xunit.runner.schema.json",
   "parallelizeAssembly": true,
   "parallelizeTestCollections": true,
-  "maxParallelThreads": 4,
+  "maxParallelThreads": 8,
   "parallelAlgorithm": "conservative"
 }