Update executable targets

Author: natecook1000

Sources/swift-build/main.swift

@@ -10,5 +10,4 @@
 
 import Commands
 
-let tool = SwiftBuildTool(args: Array(CommandLine.arguments.dropFirst()))
-tool.run()
+SwiftBuildTool.main()

Sources/swift-package/main.swift

@@ -10,5 +10,4 @@
 
 import Commands
 
-let tool = SwiftPackageTool(args: Array(CommandLine.arguments.dropFirst()))
-tool.run()
+SwiftPackageTool.main()

Sources/swift-run/main.swift

@@ -10,5 +10,4 @@
 
 import Commands
 
-let tool = SwiftRunTool(args: Array(CommandLine.arguments.dropFirst()))
-tool.run()
+SwiftRunTool.main()

Sources/swift-test/main.swift

@@ -10,5 +10,4 @@
 
 import Commands
 
-let tool = SwiftTestTool(args: Array(CommandLine.arguments.dropFirst()))
-tool.run()
+SwiftTestTool.main()