Create default variables for Crossgen, TargetsNonWindows in pipebuild

Author: wtgodbe

buildpipeline/Dotnet-CoreClr-Trusted-BuildTests.json

@@ -228,6 +228,12 @@
     },
     "RuntimeIDArg": {
       "value": "runtimeid linux-x64"
+    },
+    "TargetsNonWindowsArg": {
+      "value": " "
+    },
+    "CrossgenArg": {
+      "value": " "
     }
   },
   "retentionRules": [

buildpipeline/pipelines.json

@@ -485,7 +485,6 @@
             "Rid": "win-x64",
             "TargetQueues": "windows.10.amd64",
             "TestContainerSuffix": "windows",
-            "TargetsNonWindowsArg": " "
           },
           "ReportingParameters": {
             "OperatingSystem": "Windows",
@@ -502,7 +501,6 @@
             "Rid": "win-x64",
             "TargetQueues": "windows.10.amd64",
             "TestContainerSuffix": "windows-r2r",
-            "TargetsNonWindowsArg": " ",
             "CrossgenArg": "Crossgen"
           },
           "ReportingParameters": {