internal/rosa/llvm: early-runtimes for gentoo stage only

This bootstrap step is not required for a native Rosa OS stage0 distribution.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/llvm_test.go

@@ -8,7 +8,7 @@ import (
 )
 
 func TestLLVMInputs(t *testing.T) {
-	const wantInputCount = 470
+	const wantInputCount = 466
 
 	_, llvm := rosa.MustLoad(rosa.H("llvm"))
 	var n int