[LibOS/test/ltp] Skip make autotools for LTP

Running "make autotools" is not required when building it from the
tarball (it already includes necessary pre-built autotools stuff).

LibOS/shim/test/apps/ltp/Makefile

@@ -17,7 +17,6 @@ $(SRCDIR).tar.xz:
 
 $(SRCDIR)/configure: $(SRCDIR).tar.xz
 	tar -xmJf $<
-	cd $(SRCDIR) && make autotools
 
 $(BUILDDIR)/runltp: $(SRCDIR)/configure
 	cd $(SRCDIR) && ./configure