CIMatrixConfig null coalesce operator. Add the property CIMatrixConfigs

Author: scbedd

eng/common/scripts/Package-Properties.ps1

@@ -21,6 +21,7 @@ class PackageProps
     # additional packages required for validation of this one
     [string[]]$AdditionalValidationPackages
     [HashTable]$ArtifactDetails
+    [HashTable[]]$CIMatrixConfigs
 
     PackageProps([string]$name, [string]$version, [string]$directoryPath, [string]$serviceDirectory)
     {

eng/common/scripts/job-matrix/Create-PrJobMatrix.ps1

@@ -64,9 +64,7 @@ $packageProperties = Get-ChildItem -Recurse "$PackagePropertiesFolder" *.json `
 
 # set default matrix config for each package if there isn't an override
 $packageProperties | ForEach-Object {
-  if (-not $_.CIMatrixConfigs) {
-    $_.CIMatrixConfigs = $configs
-  }
+  $_.CIMatrixConfigs = $_.CIMatrixConfigs ?? $configs
 }
 
 # The key here is that after we group the packages by the matrix config objects, we can use the first item's MatrixConfig