Expand the Swift SDKs path to an absolute path in the lit.cfg file.

Author: kateinoigakukun

test/lit.cfg

@@ -42,6 +42,9 @@ config.swift_sdk = swift_sdk
 
 # --param swift-sdks-path=<swift-sdks-path>
 config.swift_sdks_path = lit_config.params.get("swift-sdks-path")
+if config.swift_sdks_path:
+    config.swift_sdks_path = os.path.abspath(config.swift_sdks_path)
+    lit_config.note(f"using Swift SDKs path: {config.swift_sdks_path}")
 
 # --param base-toolchain-path=PATH
 base_toolchain_path = lit_config.params.get("base-toolchain-path")