Reland "[benchmarks] Move libcxx's fork of google/benchmark and llvm/utils'""

This reverts commit e7568b68da8a216dc22cdc1c6d8903c94096c846 and relands
c6f7b720ecfa6db40c648eb05e319f8a817110e9.

The culprit was: missed that libc also had a dependency on one of the
copies of `google-benchmark`

Also opportunistically fixed indentation from prev. change.

Differential Revision: https://reviews.llvm.org/D112012

GitOrigin-RevId: 1ee32055ea1dd4db70d1939cbd4f5105c2dce160
diff --git a/benchmarks/CMakeLists.txt b/benchmarks/CMakeLists.txt
index 01aab05..ac06e5a 100644
--- a/benchmarks/CMakeLists.txt
+++ b/benchmarks/CMakeLists.txt
@@ -17,7 +17,7 @@
 ExternalProject_Add(google-benchmark
     EXCLUDE_FROM_ALL ON
     PREFIX google-benchmark
-    SOURCE_DIR ${LIBC_SOURCE_DIR}/../llvm/utils/benchmark
+    SOURCE_DIR ${LLVM_THIRD_PARTY_DIR}/benchmark
     INSTALL_DIR ${CMAKE_CURRENT_BINARY_DIR}/google-benchmark
     CMAKE_CACHE_ARGS
         -DBUILD_SHARED_LIBS:BOOL=OFF