Map parallelizable true to parallelization all to match the behaviour from Xcodeproj 8.24.3 (#1565)

Author: CraigSiemens

Sources/XcodeGenKit/SchemeGenerator.swift

@@ -260,7 +260,7 @@ public class SchemeGenerator {
 
             return XCScheme.TestableReference(
                 skipped: testTarget.skipped,
-                parallelizable: testTarget.parallelizable,
+                parallelization: testTarget.parallelizable ? .all : .none,
                 randomExecutionOrdering: testTarget.randomExecutionOrder,
                 buildableReference: testBuildEntries.buildableReference,
                 locationScenarioReference: locationScenarioReference,

Tests/Fixtures/TestProject/Project.xcodeproj/xcshareddata/xcschemes/App_Scheme.xcscheme

@@ -60,6 +60,7 @@
          </TestableReference>
          <TestableReference
             skipped = "NO"
+            parallelizable = "YES"
             testExecutionOrdering = "random">
             <BuildableReference
                BuildableIdentifier = "primary"