Use runtimes for llvm compiler-rt (#752)

Co-authored-by: Arjun <[email protected]>

Author: amd-arsuresh

script/install-llvm-src/meta.yaml

@@ -105,7 +105,7 @@ variations:
     group: compiler-rt
     default: true
     env:
-      +MLC_LLVM_ENABLE_PROJECTS:
+      +MLC_LLVM_ENABLE_RUNTIMES:
         - compiler-rt
   no-compiler-rt:
     group: compiler-rt