Allow running rust-installer (and other tools) multiple times with the same arguments

src/bootstrap/src/core/build_steps/tool.rs

@@ -1581,6 +1581,10 @@ impl Builder<'_> {
     /// `host`.
     pub fn tool_cmd(&self, tool: Tool) -> BootstrapCommand {
         let mut cmd = command(self.tool_exe(tool));
+
+        // Do not cache tool invocations, as they can have side effects
+        cmd.do_not_cache();
+
         let compiler = self.compiler(0, self.config.host_target);
         let host = &compiler.host;
         // Prepares the `cmd` provided to be able to run the `compiler` provided.