Make lit configs relocatable again after c747b7d

See https://reviews.llvm.org/D77184 for background.

Author: nico

llvm/test/CMakeLists.txt

@@ -26,6 +26,7 @@ configure_lit_site_cfg(
   MAIN_CONFIG
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.cfg.py
   PATHS
+  "CMAKE_OSX_SYSROOT"
   "LLVM_SOURCE_DIR"
   "LLVM_BINARY_DIR"
   "LLVM_TOOLS_DIR"

llvm/test/lit.site.cfg.py.in

@@ -17,7 +17,7 @@ config.errc_messages = "@LLVM_LIT_ERRC_MESSAGES@"
 config.python_executable = "@Python3_EXECUTABLE@"
 config.gold_executable = "@GOLD_EXECUTABLE@"
 config.ld64_executable = "@LD64_EXECUTABLE@"
-config.osx_sysroot = "@CMAKE_OSX_SYSROOT@"
+config.osx_sysroot = path(r"@CMAKE_OSX_SYSROOT@")
 config.ocamlfind_executable = "@OCAMLFIND@"
 config.have_ocamlopt = @HAVE_OCAMLOPT@
 config.have_ocaml_ounit = @HAVE_OCAML_OUNIT@