PS: Add test with missing flow.

Author: MathiasVP

powershell/ql/test/library-tests/dataflow/pipeline/test.ps1

@@ -28,4 +28,13 @@ function consume2 {
 
 $x = Source "21"
 $y = Source "22"
-$x, $y | consume2
+$x, $y | consume2
+
+function consumeValueFromPipelineByPropertyName {
+    Param([Parameter(ValueFromPipelineByPropertyName)] $x)
+
+    Sink $x # $ MISSING: hasValueFlow=23
+}
+
+$x = Source "23"
+[pscustomobject]@{x = $x} | consumeValueFromPipelineByPropertyName