Revert "hipcc: Turn back linking hip_ir.ll by default"

This reverts commit 528b257004.

bin/hipcc

@@ -218,7 +218,7 @@ if($HIP_PLATFORM eq "hcc"){
   }
 }
 
-if($HIP_PLATFORM eq "hcc"){
+if(($HIP_PLATFORM eq "hcc") and defined $ENV{HIP_EXPERIMENTAL}){
     $EXPORT_LL=" ";
     $ENV{HCC_EXTRA_LIBRARIES}="$HIP_PATH/lib/hip_ir.ll\n";
 }