Apply suggestions from code review

Co-authored-by: Andrew Eisenberg <aeisenberg@github.com>

Author: edoardopirovano

extensions/ql-vscode/package.json

@@ -186,7 +186,7 @@
           "scope": "window",
           "type": "string",
           "default": "",
-          "description": "Additional command line arguments to pass to the CLI when running tests."
+          "markdownDescription": "Additional command line arguments to pass to the CLI when [running tests](https://codeql.github.com/docs/codeql-cli/manual/test-run/)."
         },
         "codeQL.runningTests.numberOfThreads": {
           "scope": "window",

extensions/ql-vscode/src/cli.ts

@@ -509,7 +509,7 @@ export class CodeQLCliServer implements Disposable {
     testPaths: string[], workspaces: string[], options: TestRunOptions
   ): AsyncGenerator<TestCompleted, void, unknown> {
 
-    const subcommandArgs = this.cliConfig.additionalTestArguments.toString().split(' ').concat([
+    const subcommandArgs = this.cliConfig.additionalTestArguments.toString().split(/\s+/).concat([
       '--additional-packs', workspaces.join(path.delimiter),
       '--threads',
       this.cliConfig.numberTestThreads.toString(),