Add support for installing Node.js on macOS (#38903)

This commit adds two new functions in
`install_macos_tools.sh` that install nodejs
and common nodejs dependencies.

.buildkite/scripts/install_macos_tools.sh

@@ -106,6 +106,28 @@ config_git() {
   fi
 }
 
+withNodeJSEnv() {
+  local version=$1
+  echo "~~~ Installing nvm and Node.js"
+  curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.1/install.sh | bash
+  export NVM_DIR="$HOME/.nvm"
+  [ -s "$NVM_DIR/nvm.sh" ] && source "$NVM_DIR/nvm.sh"
+  echo "Installing Node.js version: $version"
+  nvm install "$version"
+  # export PATH="${nvmPath}:${PATH}"
+  nvm use "$version"
+  node --version
+  echo "~~~ Resuming commands"
+}
+
+installNodeJsDependencies() {
+  echo "~~~ Installing Node.js packages"
+  # needed for beats-xpack-heartbeat
+  echo "Install @elastic/synthetics"
+  npm i -g @elastic/synthetics
+  echo "~~~ Resuming commands"
+}
+
 add_bin_path
 with_go "${GO_VERSION}"
 with_mage