Split this test so I can figure out CI failure

Tests/PathTests/PathTests.swift

@@ -204,7 +204,9 @@ class PathTests: XCTestCase {
             XCTAssertThrowsError(try root.foo.copy(to: root.bar))
             try root.foo.copy(to: root.bar, overwrite: true)
         }
+    }
 
+    func testCopyToExistingDirectoryFails() throws {
         // test copy errors if directory exists at destination, even with overwrite
         try Path.mktemp { root in
             try root.foo.touch()

Tests/PathTests/XCTestManifests.swift

@@ -13,6 +13,7 @@ extension PathTests {
         ("testConcatenation", testConcatenation),
         ("testCopyInto", testCopyInto),
         ("testCopyTo", testCopyTo),
+        ("testCopyToExistingDirectoryFails", testCopyToExistingDirectoryFails),
         ("testDataExtensions", testDataExtensions),
         ("testDelete", testDelete),
         ("testDynamicMember", testDynamicMember),