Revert "Error on empty product names (#5805)"

This reverts commit d61b1ea.

Author: DougGregor

Sources/PackageLoading/PackageBuilder.swift

@@ -181,16 +181,13 @@ extension Target.Error.ModuleNameProblem: CustomStringConvertible {
 extension Product {
     /// An error in a product definition.
     enum Error: Swift.Error {
-        case emptyName
         case moduleEmpty(product: String, target: String)
     }
 }
 
 extension Product.Error: CustomStringConvertible {
     var description: String {
         switch self {
-        case .emptyName:
-            return "product names can not be empty"
         case .moduleEmpty(let product, let target):
             return "target '\(target)' referenced in product '\(product)' is empty"
         }
@@ -1150,10 +1147,6 @@ public final class PackageBuilder {
             filteredProducts = self.manifest.products.filter { set.contains($0.name) }
         }
         for product in filteredProducts {
-            if product.name.isEmpty {
-                throw Product.Error.emptyName
-            }
-
             let targets = try modulesFrom(targetNames: product.targets, product: product.name)
             // Perform special validations if this product is exporting
             // a system library target.

Tests/PackageLoadingTests/PackageBuilderTests.swift

@@ -577,24 +577,6 @@ class PackageBuilderTests: XCTestCase {
         }
     }
 
-    func testEmptyProductNameError() throws {
-        let fs = InMemoryFileSystem(emptyFiles: "/Sources/best/best.swift")
-
-        let manifest = Manifest.createRootManifest(
-            name: "pkg",
-            products: [
-                try ProductDescription(name: "", type: .library(.automatic), targets: ["best"]),
-            ],
-            targets: [
-                try TargetDescription(name: "best"),
-            ]
-        )
-
-        PackageBuilderTester(manifest, in: fs) { package, diagnostics in
-            diagnostics.check(diagnostic: "product names can not be empty", severity: .error)
-        }
-    }
-
     func testMultipleTestEntryPointsError() throws {
         let name = SwiftTarget.defaultTestEntryPointName
         let swift: AbsolutePath = AbsolutePath("/swift")