Merge pull request #27957 from compnerd/build-is-not-path

test: use `inferSwiftBinary` to find the reflection tool

Author: compnerd

test/lit.cfg

@@ -1594,8 +1594,7 @@ config.substitutions.append(('%target-swift-ide-test\(mock-sdk:([^)]+)\)',
 config.substitutions.append(('%target-swift-ide-test', "%s -swift-version %s" % (config.target_swift_ide_test, swift_version)))
 
 if not hasattr(config, 'target_swift_reflection_test'):
-    config.target_swift_reflection_test = lit.util.which(
-        swift_reflection_test_name, config.environment['PATH'])
+    config.target_swift_reflection_test = inferSwiftBinary(swift_reflection_test_name)
 
 config.substitutions.append(('%target-swift-reflection-test', config.target_swift_reflection_test))