Revert "[CMake] Use LLVM_TARGET_TRIPLE in runtimes"

This reverts commit bec8a372fc0db95852748691c0f4933044026b25.

This causes many of these errors to appear when rebuilding runtimes part
of fuchsia's toolchain:

ld.lld: error:
/usr/local/google/home/paulkirth/llvm-upstream/build/lib/x86_64-unknown-linux-gnu/libunwind.a(libunwind.cpp.o)
is incompatible with elf64-x86-64

This can be reproduced by making a complete toolchain, saving any source
file with no changes, then rerunning ninja distribution.

GitOrigin-RevId: 96d63993dd3698bbf2d6a83c035cd05faed7317b
diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index 9eb48b8..fd7daa5 100644
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -689,8 +689,8 @@
   set(CAN_SYMBOLIZE 1)
 endif()
 
-find_program(GNU_LD_EXECUTABLE NAMES ${LLVM_TARGET_TRIPLE}-ld.bfd ld.bfd DOC "GNU ld")
-find_program(GOLD_EXECUTABLE NAMES ${LLVM_TARGET_TRIPLE}-ld.gold ld.gold DOC "GNU gold")
+find_program(GNU_LD_EXECUTABLE NAMES ${LLVM_DEFAULT_TARGET_TRIPLE}-ld.bfd ld.bfd DOC "GNU ld")
+find_program(GOLD_EXECUTABLE NAMES ${LLVM_DEFAULT_TARGET_TRIPLE}-ld.gold ld.gold DOC "GNU gold")
 
 if(COMPILER_RT_SUPPORTED_ARCH)
   list(REMOVE_DUPLICATES COMPILER_RT_SUPPORTED_ARCH)