🧪Add results-directory option to dotnet test tasks (microsoft#812)

This commit adds the --results-directory option to the dotnet test tasks
in the .vscode/tasks.json file. This option specifies the directory
where the test results and code coverage reports are stored. By setting
this option, the test tasks can avoid cluttering the default TestResults
folder in the solution root. The commit also adds a new test task that
runs all the tests in the dotnet folder with code coverage enabled.

.vscode/tasks.json

@@ -121,6 +121,8 @@
       "type": "process",
       "args": [
         "test",
+        "--results-directory",
+        "${workspaceFolder}/dotnet/TestResults/",
         "--collect",
         "XPlat Code Coverage;Format=lcov",
         "--filter",
@@ -143,6 +145,8 @@
       "type": "process",
       "args": [
         "test",
+        "--results-directory",
+        "${workspaceFolder}/dotnet/TestResults/",
         "--collect",
         "XPlat Code Coverage;Format=lcov",
         "--filter",
@@ -159,12 +163,37 @@
         "cwd": "${workspaceFolder}/dotnet/src/Extensions/Extensions.UnitTests/"
       }
     },
+    {
+      "label": "Test - ALL (Code Coverage)",
+      "command": "dotnet",
+      "type": "process",
+      "args": [
+        "test",
+        "--results-directory",
+        "${workspaceFolder}/dotnet/TestResults/",
+        "--collect",
+        "XPlat Code Coverage;Format=lcov",
+        "--filter",
+        "${input:filter}"
+      ],
+      "problemMatcher": "$msCompile",
+      "group": "test",
+      "presentation": {
+        "reveal": "always",
+        "panel": "shared"
+      },
+      "options": {
+        "cwd": "${workspaceFolder}/dotnet/"
+      }
+    },
     {
       "label": "Test - Semantic-Kernel Integration (Code Coverage)",
       "command": "dotnet",
       "type": "process",
       "args": [
         "test",
+        "--results-directory",
+        "${workspaceFolder}/dotnet/TestResults/",
         "--collect",
         "XPlat Code Coverage;Format=lcov",
         "--filter",