[llvm] [CI] Only run normal check targets if requested (PR #168412)

[via llvm-commits]

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@@ -64,9 +64,11 @@ cmake -S "${MONOREPO_ROOT}"/llvm -B "${BUILD_DIR}" \
 
 start-group "ninja"
 
-# Targets are not escaped as they are passed as separate arguments.
-ninja -C "${BUILD_DIR}" -k 0 ${targets} |& tee ninja.log
-cp ${BUILD_DIR}/.ninja_log ninja.ninja_log
+if [[ "${targets}" != "" ]]; then
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cmtice wrote:

Ok. I think we *should* switch to '-z' everywhere, but I'm ok with doing that in another PR.

https://github.com/llvm/llvm-project/pull/168412