[PackageGraphTests] Update linuxmain

Author: aciidgh

Tests/PackageGraphTests/XCTestManifests.swift

@@ -9,6 +9,7 @@ extension DependencyResolverTests {
  ("testBasics", testBasics),
  ("testCompleteness", testCompleteness),
  ("testContainerConstraintSet", testContainerConstraintSet),
+ ("testCycle", testCycle),
  ("testDiagnostics", testDiagnostics),
  ("testExactConstraint", testExactConstraint),
  ("testIncompleteMode", testIncompleteMode),