Add ./tool/override_analyzer_dependency.sh to checkout latest analyzer + set is as override

tool/dependency_overrides.sh

Index: tool/dependency_overrides.sh
diff --git a/tool/dependency_overrides.sh b/tool/dependency_overrides.sh
new file mode 100644
index 0000000000000000000000000000000000000000..75845514c686be0e501451bb2f36c778d8ee49fe
--- /dev/null
+++ b/tool/dependency_overrides.sh
@@ -0,0 +1,61 @@
+#!/bin/bash
+
+function add_dependency_override() {
+  local name=$1
+  local path=$2
+  if ! cat pubspec.yaml | grep "dependency_overrides:" ; then
+    echo "dependency_overrides:" >> pubspec.yaml
+  fi
+  local pubspec=`cat pubspec.yaml | grep -v "$name: .path: "`
+  echo "$pubspec" > pubspec.yaml
+  if [[ -n "$path" ]]; then
+    echo "  $name: {path: $path}" >> pubspec.yaml
+  fi
+}
+
+function checkout_dependency_override_from_github() {
+  local dependency_name=$1
+  local org_project=$2
+  local branch=$3
+  local path=${4:-/}
+
+  local url=https://github.com/$org_project
+
+  echo "dependency_name = $dependency_name"
+  echo "url = $url$path"
+  echo "branch = $branch"
+
+  local dep_dir=dependency_overrides/$dependency_name
+
+  [[ -d `dirname $dep_dir` ]] || mkdir `dirname $dep_dir`
+
+  if [[ -d $dep_dir ]]; then
+    # Check there's no local modifications before removing existing directory.
+    (
+      cd $dep_dir
+      if git status -s | grep . ; then
+        echo "Found local modifications in $dep_dir: aborting"
+        exit 1
+      fi
+    )
+    rm -fR $dep_dir
+  fi
+
+  if [[ "$path" == "/" ]]; then
+    # Checkout only the branch, with no history:
+    git clone --depth 1 --branch $branch $url $dep_dir
+  else
+    (
+      mkdir $dep_dir
+      cd $dep_dir
+
+      # Sparse-checkout only the path + branch, with no history:
+      git init
+      git remote add origin $url
+      git config core.sparsecheckout true
+      echo $path >> .git/info/sparse-checkout
+      git pull --depth=1 origin $branch
+    )
+  fi
+  add_dependency_override $dependency_name $dep_dir$path
+}