feat(run): Include the workspace root .bin in env path (#4848)

**Summary**

Partial resolution for #4543.

Previously, when running `yarn run` the env PATH would be set to look in node_modules/.bin, however, in workspaces the root workspace .bin path was not being included.

This PR adds the workspace root
node_modules/.bin path after the individual package's path.

This is generally needed because #4730 ensures bin links in a workspace will be at the workspace root. With this PR, you can now `yarn run` commands in an individual package again.

**Test plan**

Manually tested by adding a script that runs `echo $PATH`

__tests__/commands/run.js

@@ -26,6 +26,17 @@ const fixturesLoc = path.join(__dirname, '..', 'fixtures', 'run');
 const runRun = buildRun.bind(null, BufferReporter, fixturesLoc, (args, flags, config, reporter): Promise<void> => {
   return run(config, reporter, flags, args);
 });
+const runRunInWorkspacePackage = function(cwd, ...args): Promise<void> {
+  return buildRun.bind(null, BufferReporter, fixturesLoc, (args, flags, config, reporter): Promise<void> => {
+    const originalCwd = config.cwd;
+    config.cwd = path.join(originalCwd, cwd);
+    const retVal = run(config, reporter, flags, args);
+    retVal.then(() => {
+      config.cwd = originalCwd;
+    });
+    return retVal;
+  })(...args);
+};
 
 test('lists all available commands with no arguments', (): Promise<void> => {
   return runRun([], {}, 'no-args', (config, reporter): ?Promise<void> => {
@@ -133,3 +144,14 @@ test('adds quotes if args have spaces and quotes', (): Promise<void> => {
     expect(execCommand).toBeCalledWith(...args);
   });
 });
+
+test('adds workspace root node_modules/.bin to path when in a workspace', (): Promise<void> => {
+  return runRunInWorkspacePackage('packages/pkg1', ['env'], {}, 'workspace', (config, reporter): ?Promise<void> => {
+    const logEntry = reporter.getBuffer().find(entry => entry.type === 'log');
+    const parsedLogData = JSON.parse(logEntry ? logEntry.data.toString() : '{}');
+    const envPaths = (parsedLogData.PATH || parsedLogData.Path).split(path.delimiter);
+
+    expect(envPaths).toContain(path.join(config.cwd, 'node_modules', '.bin'));
+    expect(envPaths).toContain(path.join(config.cwd, 'packages', 'pkg1', 'node_modules', '.bin'));
+  });
+});

__tests__/fixtures/run/workspace/package.json

@@ -0,0 +1,5 @@
+{
+  "workspaces": [
+    "packages/*"
+  ]
+}

__tests__/fixtures/run/workspace/packages/pkg1/package.json

@@ -0,0 +1 @@
+{}

src/util/execute-lifecycle-script.js

@@ -148,6 +148,9 @@ export async function makeEnv(
   // add .bin folders to PATH
   for (const registry of Object.keys(registries)) {
     const binFolder = path.join(config.registries[registry].folder, '.bin');
+    if (config.workspacesEnabled && config.workspaceRootFolder) {
+      pathParts.unshift(path.join(config.workspaceRootFolder, binFolder));
+    }
     pathParts.unshift(path.join(config.linkFolder, binFolder));
     pathParts.unshift(path.join(cwd, binFolder));
   }