fix: improve colon handling in dependency discovery for windows

Author: GregoryConrad

native_toolchain_rust/lib/src/dependency_discoverer.dart

@@ -16,13 +16,7 @@ interface class DependencyDiscoverer {
     logger.fine('Discovering dependencies in $dependencyFilePath');
     return File(dependencyFilePath)
         .readAsLinesSync()
-        .map((line) {
-          final splitIndex = line.indexOf(':');
-          if (splitIndex < 0) return null;
-          return line.substring(splitIndex + 1).trim();
-        })
-        .nonNulls
-        .expand((files) => files.split(' '))
+        .expand((line) => line.trim().split(' ').skip(1))
         .followedBy([dependencyFilePath])
         .map(path.toUri);
   }

native_toolchain_rust/test/dependency_discoverer_test.dart

@@ -56,24 +56,6 @@ target/debug/librust_lib.a: /path/to/some/other/file.rs
       );
     });
 
-    test('discover ignores lines without a colon', () {
-      final dependencyFilePath = path.join(tempDir.path, 'test.d');
-      File(dependencyFilePath).writeAsStringSync('''
-invalid line
-target/debug/librust_lib.a: src/lib.rs
-''');
-
-      final dependencies = dependencyDiscoverer.discover(dependencyFilePath);
-
-      expect(
-        dependencies,
-        containsAll([
-          path.toUri('src/lib.rs'),
-          path.toUri(dependencyFilePath),
-        ]),
-      );
-      expect(dependencies.length, 2);
-    });
 
     test('discover handles an empty dependency file', () {
       final dependencyFilePath = path.join(tempDir.path, 'test.d');