Check en0..en8 when generating ip.txt for iOS debug builds (#28764)

Summary:
When generating ip.txt in an iOS debug build, search en0 through en8 for an IP address rather than only checking en0 and en1.  For example, on my Mac, the IP address I needed to use was on en5 and the IP address actually detected was a private network of one of my Parallels virtual machines (interface vnic0).

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[iOS] [Fixed] - Search en0 through en8 for the Metro Bundler's IP address when generating iOS debug builds
Pull Request resolved: #28764

Test Plan: Should make no difference to users for whom react-native-xcode.sh already worked. On a Mac with multiple virtual machines installed, should prevent ip.txt getting the private IP address of a virtual machine.

Differential Revision: D21280671

Pulled By: shergin

fbshipit-source-id: e6fe9c8344146626df96129968981462463201f7

scripts/react-native-xcode.sh

@@ -14,10 +14,12 @@ DEST=$CONFIGURATION_BUILD_DIR/$UNLOCALIZED_RESOURCES_FOLDER_PATH
 
 # Enables iOS devices to get the IP address of the machine running Metro
 if [[ "$CONFIGURATION" = *Debug* && ! "$PLATFORM_NAME" == *simulator ]]; then
-  IP=$(ipconfig getifaddr en0)
-  if [[ -z "$IP" || -n "`ifconfig $value | grep 'baseT'`" ]]; then
-    IP=$(ipconfig getifaddr en1)
-  fi
+  for num in 0 1 2 3 4 5 6 7 8; do
+    IP=$(ipconfig getifaddr en${num})
+    if [ ! -z "$IP" ]; then
+      break
+    fi
+  done
   if [ -z "$IP" ]; then
     IP=$(ifconfig | grep 'inet ' | grep -v ' 127.' | grep -v ' 169.254.' |cut -d\   -f2  | awk 'NR==1{print $1}')
   fi