Fail early if nvm fails to install Node.js binary

Instead of trying to build Node.js from source, fail early when
nvm fails to install using the Node.js binary.

This avoids jobs that take >1h to provide feedback rather than
the usual few minutes in case of error at the install stage.

test/presubmit-tests.sh

@@ -68,7 +68,9 @@ function get_node() {
   curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.4/install.sh | bash
   export NVM_DIR="$HOME/.nvm"
   source "$NVM_DIR/nvm.sh"
-  nvm install
+  # if nvm install fails using the Node.js binary, the `-b` causes it to exit
+  # instead of trying to build from source
+  nvm install -b
 }
 
 function node_npm_install() {