Clone flutter in different directory

.travis.yml

 matrix:
   include:
-    # Job 1) Check format and run tests
+    # Job 1) Analyze the code
+    - os: linux
+      jdk: oraclejdk8
+      sudo: false
+      addons:
+        apt:
+          # Flutter depends on /usr/lib/x86_64-linux-gnu/libstdc++.so.6 version GLIBCXX_3.4.18
+          sources:
+            - ubuntu-toolchain-r-test # if we don't specify this, the libstdc++6 we get is the wrong version
+            - llvm-toolchain-precise # for clang-format-5.0
+          packages:
+            - libstdc++6
+            - fonts-droid
+      before_script:
+        - git clone https://github.com/flutter/flutter.git --depth 1 ../flutter
+        - export PATH=`pwd`/../flutter/bin:`pwd`/../flutter/bin/cache/dart-sdk/bin:$PATH
+        - flutter doctor
+        - flutter packages get
+      script:
+        - flutter analyze
+    # Job 2) Check format and run tests
     - os: linux
       jdk: oraclejdk8
       sudo: false
@@ -15,12 +35,12 @@ matrix:
             - fonts-droid
             - clang-format-5.0
       before_script:
-        - git clone https://github.com/flutter/flutter.git --depth 1
-        - export PATH=`pwd`/flutter/bin:`pwd`/flutter/bin/cache/dart-sdk/bin:$PATH
+        - git clone https://github.com/flutter/flutter.git --depth 1 ../flutter
+        - export PATH=`pwd`/../flutter/bin:`pwd`/../flutter/bin/cache/dart-sdk/bin:$PATH
         - flutter doctor
       script:
         - ./scripts/format_code.sh
-    # Job 2) Build example APKs and run Java tests
+    # Job 3) Build example APKs and run Java tests
     - os: linux
       jdk: oraclejdk8
       sudo: false
@@ -34,9 +54,9 @@ matrix:
             - libstdc++6
             - fonts-droid
       before_script:
-        - git clone https://github.com/flutter/flutter.git --depth 1
+        - git clone https://github.com/flutter/flutter.git --depth 1 ../flutter
+        - export PATH=`pwd`/../flutter/bin:`pwd`/../flutter/bin/cache/dart-sdk/bin:$PATH
         - export ANDROID_HOME=`pwd`/android-sdk
-        - export PATH=`pwd`/flutter/bin:`pwd`/flutter/bin/cache/dart-sdk/bin:$PATH
         - wget https://dl.google.com/android/repository/sdk-tools-linux-3859397.zip
         - mkdir android-sdk
         - unzip -qq sdk-tools-linux-3859397.zip -d android-sdk
@@ -60,7 +80,7 @@ matrix:
         - flutter doctor
       script:
         - flutter build apk
-    # Job 3) Build example IPAs
+    # Job 4) Build example IPAs
     - os: osx
       language: generic
       osx_image: xcode9.3
@@ -70,8 +90,8 @@ matrix:
         - brew install libimobiledevice
         - brew install ideviceinstaller
         - brew install ios-deploy
-        - git clone https://github.com/flutter/flutter.git --depth 1
-        - export PATH=`pwd`/flutter/bin:`pwd`/flutter/bin/cache/dart-sdk/bin:$PATH
+        - git clone https://github.com/flutter/flutter.git --depth 1 ../flutter
+        - export PATH=`pwd`/../flutter/bin:`pwd`/../flutter/bin/cache/dart-sdk/bin:$PATH
       script:
         - flutter build ios --no-codesign
 cache: