support attaching by name for platform android (#160931)

## Bug
Trying to attach to an android process by name fails:
```
(lldb) process attach -n com.android.bluetooth
error: attach failed: could not find a process named com.android.bluetooth
```

## Root Cause
PlatformAndroid does not implement the `FindProcesses` method.

As described in `include/lldb/Target/Platform.h`:
```
  // The base class Platform will take care of the host platform. Subclasses
  // will need to fill in the remote case.
  virtual uint32_t FindProcesses(const ProcessInstanceInfoMatch &match_info,
                                 ProcessInstanceInfoList &proc_infos);
```

## Fix
Implement the `FindProcesses` method in PlatformAndroid. Use adb to get
the pid of the process name on the device with the adb client connection
using `adb shell pidof <name>`.

## Reproduce
With an android device connected, run the following

Install and start lldb-server on device
```
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
```

Start lldb, and run
```
platform select remote-android
platform connect connect://127.0.0.1:9500
log enable lldb platform
```

Connect to the process by name:
```
process attach -n com.android.bluetooth
```

## Test Plan
Before:
```
(lldb) process attach -n com.android.bluetooth
error: attach failed: could not find a process named com.android.bluetooth
```

After:
```
(lldb) process attach -n com.android.bluetooth
lldb             AdbClient::ResolveDeviceID Resolved device ID: 127.0.0.1
lldb             AdbClient::AdbClient(device_id='127.0.0.1') - Creating AdbClient with device ID
lldb             Connecting to ADB server at connect://127.0.0.1:5037
lldb             Connected to Android device "127.0.0.1"
lldb             Forwarding remote TCP port 38315 to local TCP port 35243
lldb             AdbClient::~AdbClient() - Destroying AdbClient for device: 127.0.0.1
lldb             gdbserver connect URL: connect://127.0.0.1:35243
lldb             AdbClient::AdbClient(device_id='127.0.0.1') - Creating AdbClient with device ID
lldb             Connecting to ADB server at connect://127.0.0.1:5037
lldb             Selecting device: 127.0.0.1
lldb             PlatformAndroid::FindProcesses found process 'com.android.bluetooth' with PID 2223
lldb             AdbClient::~AdbClient() - Destroying AdbClient for device: 127.0.0.1
llvm-worker-48   PlatformRemoteGDBServer::GetModuleSpec - got module info for (/apex/com.android.art/lib64/libc++.so:aarch64-unknown-linux-android) : file = '/apex/com.android.art/lib64/libc++.so', arch = aarch64-unknown-linux-android, uuid = 552995D0-A86D-055F-1F03-C13783A2A16C, object size = 754128
llvm-worker-9    PlatformRemoteGDBServer::GetModuleSpec - got module info for (/apex/com.android.art/lib64/liblzma.so:aarch64-unknown-linux-android) : file = '/apex/com.android.art/lib64/liblzma.so', arch = aarch64-unknown-linux-android, uuid = E51CAC98-666F-6C3F-F605-1498079542E0, object size = 179944
Process 2223 stopped
```

0 files changed, 0 insertions, 0 deletions