[chore] Fix flakiness of tests on Windows requiring ports in the dyna…

…mic range (open-telemetry#35061)

**Description:**
The need for this was noticed due to the following CI failures on the
`receiver/opencensus` lifecycle tests:

*
https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/10723100311/job/29735640887#step:6:619
*
https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/10725662745/job/29744029983#step:6:318

The default port used by the `opencensusreceiver` is in a range that
Windows machines can excluded, or reserved to other services via the
`WinNAT` service. This change adds a PowerShell script to release the
default ports for the `opencensusreceiver` (55678) and the
`zpagesextension` (55679) on the Windows GH workflows. While this was
affecting only the `opencensusreceiver` at this time, the cost of
running this script is small, less than 5s, and later we can easly add
other ports if the need arrives. This was already added to the core repo
via open-telemetry/opentelemetry-collector#10839

**Link to tracking Issue:**
N/A

**Testing:**
CI

**Documentation:**
N/A

.github/workflows/build-and-test-windows.yml

@@ -69,6 +69,9 @@ jobs:
             ~\go\pkg\mod
             ~\AppData\Local\go-build
           key: go-build-cache-${{ runner.os }}-${{ matrix.group }}-go-${{ hashFiles('**/go.sum') }}
+      - name: Ensure required ports in the dynamic range are available
+        run: |
+          & ${{ github.workspace }}\.github\workflows\scripts\win-required-ports.ps1
       - name: Run Unit tests
         run: make -j2 gotest GROUP=${{ matrix.group }}
   windows-unittest:

.github/workflows/scripts/win-required-ports.ps1

@@ -0,0 +1,20 @@
+<#
+.SYNOPSIS
+    This script ensures that the ports required by the default configuration of the collector are available.
+.DESCRIPTION
+    Certain runs on GitHub Actions sometimes have ports required by the default configuration reserved by other
+    applications via the WinNAT service.
+#>
+
+#Requires -RunAsAdministrator
+
+netsh interface ip show excludedportrange protocol=tcp
+
+Stop-Service winnat
+
+# Only port in the dynamic range that is being, from time to time, reserved by other applications.
+netsh interface ip add excludedportrange protocol=tcp startport=55678 numberofports=2
+
+Start-Service winnat
+
+netsh interface ip show excludedportrange protocol=tcp