doc: replace isolateserver.py with isolate

python client is being deprecated.

Bug: 984869
Change-Id: I94a7445b903d8806fe520788998e1e0e4b96326c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2029566
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736814}

docs/android_debugging_instructions.md

@@ -216,8 +216,8 @@ file as follows:
    test.
 4. Download the `.mapping` file for the APK used by the test (e.g.,
    `ChromePublic.apk.mapping`). Note that you may need to use the
-   `tools/swarming_client/isolateserver.py` script to download the mapping
-   file if it's too big. The viewer will provide instructions for this.
+   `tools/luci-go/isolated` to download the mapping file if it's too big. The
+   viewer will provide instructions for this.
 
 **Googlers Only**: For official build mapping files, see
 [go/chromejavadeobfuscation](https://goto.google.com/chromejavadeobfuscation).