Revert "Workaround for broken implicit import auto static linking"

This reverts commit fde4ec9.

Author: kateinoigakukun

test/lit.cfg

@@ -1581,13 +1581,6 @@ elif run_os == 'wasi':
         '-target', config.variant_triple,
         '-Xcc', '--sysroot=%s' % config.variant_sdk,
         '-Xclang-linker', '--sysroot=%s' % config.variant_sdk,
-        # workaroud: Even though StdlibUnittest uses _Concurrency,
-        # _Concurrency module won't be listed in IMPORTED_MODULE.
-        # And -parse-stdlib disables implicit imports, so autolink
-        # system is broken when static link & -parse-stdlib & importing _Concurrency.
-        # This issue causes link failure that reports there are missing swift_task_XX
-        # symbols.
-        '-lswift_Concurrency',
         '-toolchain-stdlib-rpath', config.resource_dir_opt, 
         mcp_opt, config.swift_test_options,
         config.swift_driver_test_options, swift_execution_tests_extra_flags])