Dump JVM output when bazel fails on Windows (#41844)

### What does this PR do?
This is to diagnose
[recurring](https://gitlab.ddbuild.io/DataDog/datadog-agent/-/jobs/1166997067):
```
Starting local Bazel server (8.3.1) and connecting to it...
... still trying to connect to local Bazel server (45008) after 10 seconds ...
... still trying to connect to local Bazel server (45008) after 20 seconds ...
... still trying to connect to local Bazel server (45008) after 30 seconds ...
... still trying to connect to local Bazel server (45008) after 40 seconds ...
... still trying to connect to local Bazel server (45008) after 50 seconds ...
... still trying to connect to local Bazel server (45008) after 60 seconds ...
... still trying to connect to local Bazel server (45008) after 70 seconds ...
... still trying to connect to local Bazel server (45008) after 80 seconds ...
... still trying to connect to local Bazel server (45008) after 90 seconds ...
... still trying to connect to local Bazel server (45008) after 100 seconds ...
... still trying to connect to local Bazel server (45008) after 110 seconds ...
FATAL: couldn't connect to server (45008) after 120 seconds.
```
### Motivation
The change hopefully provides more actionable material when it happens,
see #incident-42947.

### Additional Notes
There's no need to wait for 2 minutes prior to bailing out, so
decreasing to 30 seconds will probably allow us to reproduce more
frequently.

Also, we'll print any running `bazel.exe` or `java.exe` before and after
the `bazel` command to know whether there should be additional cleanup
to consider adding.

Author: rdesgroppes

tools/bazel.bat

@@ -42,12 +42,16 @@ if exist "!BAZEL_REPO_CONTENTS_CACHE!" (
 
 rem Pass CI-specific options through `.user.bazelrc` so any nested `bazel run` and next `bazel shutdown` also honor them
 (
+  echo startup --connect_timeout_secs=30
   echo startup --output_user_root=!BAZEL_OUTPUT_USER_ROOT!
   echo common --config=cache
   echo common --repo_contents_cache=!ext_repo_contents_cache!
   echo build --disk_cache=!BAZEL_DISK_CACHE!
 ) >"!CI_PROJECT_DIR!\user.bazelrc"
 
+:: Diagnostics: print any stalled client/server before `bazel` execution
+>&2 powershell -NoProfile -Command "Get-Process bazel,java -ErrorAction SilentlyContinue | Select-Object 🟡,ProcessName,StartTime"
+
 rem Payload: execute `bazel` and remember exit status
 "!BAZEL_REAL!" %*
 set "bazel_exit=!errorlevel!"
@@ -56,6 +60,13 @@ rem Stop `bazel` (if still running) to close files and proceed with cleanup
 >&2 "!BAZEL_REAL!" shutdown --ui_event_filters=-info
 >&2 del /f /q "!CI_PROJECT_DIR!\user.bazelrc"
 
+:: Diagnostics: print any stalled client/server after `bazel` execution and dump JVM output on failure
+>&2 powershell -NoProfile -Command "Get-Process bazel,java -ErrorAction SilentlyContinue | Select-Object 🟡,ProcessName,StartTime"
+if !bazel_exit! neq 0 (
+  >&2 echo 🟡 JVM output:
+  >&2 type "!BAZEL_OUTPUT_USER_ROOT!\server\jvm.out"
+)
+
 rem Reintegrate `--repo_contents_cache` to original directory
 if exist "!ext_repo_contents_cache!" (
   call :robomove "!ext_repo_contents_cache!" "!BAZEL_REPO_CONTENTS_CACHE!"