fix: Add Node 10 support (#5769)

**Summary**

1. Added node 10 to CircleCI
2. Fixed a test that was using the `net.createServer` method. This was having issues, likely because of this: nodejs/node#20334 - it now uses a "normal" `http` server instead, serving the same purpose.
3. Changed the `readFirstAvailableStream` method in `util/fs.js`. I'm guessing this is related to the same issue as 2, but there have been quite some changes in `10` that might be causing this - so it's just a guess. Since this piece of code could be clearer and more conceise anyway, I opted to just change it. Now instead of relying on the stream `error` event to check if a file exists, it just explicitly checks it before starting the stream.
4. Upgraded `upath` from `1.0.2` to `1.0.5` which supports node 10 (found through its `engines` field when installing).
5. Upgraded Jest
6. Fixed a bug regarding replacing symlinks to non-existent targets on Windows
7. Removed a redundant test
8. Fixed two test cases that were failing frequently on macOS builds

fixes #5761
fixes #5477

**Test plan**

CI should be green (including and especially the new node10 job!)

.circleci/config.yml

@@ -122,11 +122,21 @@ jobs:
           root: ~/project
           paths:
             - yarn
+  test-pkg-tests-linux-node10:
+    <<: *docker_defaults
+    docker:
+      - image: node:10
+    <<: *pkg_tests
   test-pkg-tests-linux-node8:
     <<: *docker_defaults
     <<: *pkg_tests
+  test-linux-node10:
+    <<: *docker_defaults
+    <<: *test_steps
   test-linux-node8:
     <<: *docker_defaults
+    docker:
+      - image: node:8
     <<: *test_steps
   test-linux-node6:
     <<: *docker_defaults
@@ -138,6 +148,18 @@ jobs:
     docker:
       - image: node:4
     <<: *test_steps
+  test-macos-node10:
+    <<: *macos_defaults
+    steps:
+      - run:
+          name: Install Node 10
+          command: |
+            brew uninstall --ignore-dependencies node
+            brew update
+            HOMEBREW_NO_AUTO_UPDATE=1 brew install node@10
+      - *attach_workspace
+      - *test_build
+      - *test_run
   test-macos-node8:
     <<: *macos_defaults
     steps:
@@ -221,10 +243,18 @@ workflows:
           filters: *default_filters
           requires:
             - install
+      - test-pkg-tests-linux-node10:
+          filters: *default_filters
+          requires:
+            - install
       - test-pkg-tests-linux-node8:
           filters: *default_filters
           requires:
             - install
+      - test-linux-node10:
+          filters: *default_filters
+          requires:
+            - install
       - test-linux-node8:
           filters: *default_filters
           requires:
@@ -237,14 +267,18 @@ workflows:
           filters: *default_filters
           requires:
             - install
-      - test-macos-node6:
+      - test-macos-node10:
           filters: *default_filters
           requires:
             - install
       - test-macos-node8:
           filters: *default_filters
           requires:
             - install
+      - test-macos-node6:
+          filters: *default_filters
+          requires:
+            - install
       - build:
           filters: *default_filters
           requires:
@@ -255,10 +289,13 @@ workflows:
             branches:
               ignore: /.*/
           requires:
+            - test-pkg-tests-linux-node10
             - test-pkg-tests-linux-node8
+            - test-linux-node10
             - test-linux-node8
             - test-linux-node6
             - test-linux-node4
+            - test-macos-node10
             - test-macos-node8
             - test-macos-node6
             - lint

Dockerfile.dev

@@ -1,7 +1,7 @@
 # Dockerfile for building Yarn.
 # docker build -t yarnpkg/dev -f Dockerfile.dev .
 
-FROM node:8
+FROM node:10
 
 # Debian packages
 RUN apt-get -y update && \

__tests__/commands/_helpers.js

@@ -181,6 +181,7 @@ export async function run<T, R>(
   } catch (err) {
     throw new Error(`${err && err.stack} \nConsole output:\n ${out}`);
   } finally {
+    reporter.close();
     await fs.unlink(cwd);
   }
 }