[lldb][Android] Fix platform process list regression (#164333)

## Summary

Fix `FindProcesses` to respect Android's `hidepid=2` security model and
enable name matching for Android apps.

## Problem

1. Called `adb shell pidof` or `adb shell ps` directly, bypassing
Android's process visibility restrictions
2. Name matching failed for Android apps - searched for
`com.example.myapp` but GDB Remote Protocol reports `app_process64`

Android apps fork from Zygote, so `/proc/PID/exe` points to
`app_process64` for all apps. The actual package name is only in
`/proc/PID/cmdline`. The previous implementation applied name filters
without supplementing with cmdline, so searches failed.

## Fix

- Delegate to lldb-server via GDB Remote Protocol (respects `hidepid=2`)
- Get all visible processes, supplement zygote/app_process entries with
cmdline, then apply name matching
- Only fetch cmdline for zygote apps (performance), parallelize with
`xargs -P 8`
- Remove redundant code (GDB Remote Protocol already provides GID/arch)

## Test Results

### Before this fix:

```
(lldb) platform process list
error: no processes were found on the "remote-android" platform

(lldb) platform process list -n com.example.hellojni
1 matching process was found on "remote-android"
PID    PARENT USER       TRIPLE                         NAME
====== ====== ========== ============================== ============================
5276   359    u0_a192                                   com.example.hellojni
                         ^^^^^^^^ Missing triple!
```

### After this fix:

```
(lldb) platform process list
PID    PARENT USER       TRIPLE                         NAME
====== ====== ========== ============================== ============================
1      0      root       aarch64-unknown-linux-android  init
2      0      root                                      [kthreadd]
359    1      system     aarch64-unknown-linux-android  app_process64
5276   359    u0_a192    aarch64-unknown-linux-android  com.example.hellojni
5357   5355   u0_a192    aarch64-unknown-linux-android  sh
5377   5370   u0_a192    aarch64-unknown-linux-android  lldb-server
                          ^^^^^^^^ User-space processes now have triples!

(lldb) platform process list -n com.example.hellojni
1 matching process was found on "remote-android"
PID    PARENT USER       TRIPLE                         NAME
====== ====== ========== ============================== ============================
5276   359    u0_a192    aarch64-unknown-linux-android  com.example.hellojni


(lldb) process attach -n com.example.hellojni
Process 5276 stopped
* thread #1, name = 'example.hellojni', stop reason = signal SIGSTOP
```

## Test Plan

With an Android device/emulator connected:

1. Start lldb-server on device:
```bash
adb push lldb-server /data/local/tmp/
adb shell chmod +x /data/local/tmp/lldb-server
adb shell /data/local/tmp/lldb-server platform  --listen 127.0.0.1:9500 --server
```

2. Connect from LLDB:
```
(lldb) platform select remote-android
(lldb) platform connect connect://127.0.0.1:9500
(lldb) platform process list
```

3. Verify:
- `platform process list` returns all processes with triple information
- `platform process list -n com.example.app` finds Android apps by
package name
- `process attach -n com.example.app` successfully attaches to Android
apps

## Impact

Restores `platform process list` on Android with architecture
information and package name lookup. All name matching modes now work
correctly.

Fixes https://github.com/llvm/llvm-project/issues/164192