[Android] fix NDK extract location

The Android NDK is being extracted with an extra intermediate directory:

  $BinaryCache\android-ndk-r26b\android-ndk-r26b

The Android build fails because it expects the NDK contents to live
immediately under the directory:

  $BinaryCache\android-ndk-r26b

The extra android-ndk-r26b sub-dir comes from the NDK zip archive
itself, which we have no control over. To work-around we could either
extract the archive directly into $BinaryCache or move the contents
after extraction. This change does the latter in order to preserve the
last-write-time optimization used to skip extraction when not needed.

Author: andrurogerz

utils/build.ps1

@@ -649,6 +649,14 @@ function Fetch-Dependencies {
     Write-Output "Extracting '$ZipFileName' ..."
     New-Item -ItemType Directory -ErrorAction Ignore -Path $BinaryCache | Out-Null
     Expand-Archive -Path $source -DestinationPath $destination -Force
+
+    # If extraction created a subdir in $ExtractPath with the same name, move
+    # its contents up one level and remove the intermediate directory.
+    $extractSubDir = Join-Path -Path $destination -ChildPath $ExtractPath
+    if (Test-Path $extractSubDir) {
+      Move-Item -Path "$extractSubDir\*" -Destination $destination -Force
+      Remove-Item -Path $extractSubDir
+    }
   }
 
   function Extract-Toolchain {