Part of work on [#101077](https://github.com/flutter/flutter/pull/141194). This is done as a separate PR to avoid a massive diff.
## Context
1. The `FakeCommand` class accepts a list of patterns that's used to match a command given to its `FakeProcessManager`. Since `FakeCommand` can match a list of patterns, not just specifically strings, it can be used to match commands where the exact value of some arguments can't (easily) known ahead of time. For example, a part of the tool may invoke a command with an argument that is the path of a temporarily file that has a randomly-generated basename.
2. The `FakeCommand` class provides on `onRun` parameter, which is a callback that is run when the `FakeProcessManager` runs a command that matches the `FakeCommand` in question.
## Issue
In the event that a `FakeCommand` is constructed using patterns, the test code can't know the exact values used for arguments in the command. This PR proposes changing the type of `onRun` from `VoidCallback?` to `void Function(List<String>)?`. When run, the value `List<String>` parameter will be the full command that the `FakeCommand` matched.
Example:
```dart
FakeCommand(
command: <Pattern>[
artifacts.getArtifactPath(Artifact.engineDartBinary),
'run',
'vector_graphics_compiler',
RegExp(r'--input=/.*\.temp'),
RegExp(r'--output=/.*\.temp'),
],
onRun: (List<String> command) {
final outputPath = (() {
// code to parse `--output` from `command`
})();
testFileSystem.file(outputPath).createSync(recursive: true);
},
)
```
Starting in Xcode 15, the simulator is no longer included in Xcode and must be downloaded and installed separately.
If you try to run flutter and the simulator is missing, you'll get an error like
```
xcodebuild: error: Unable to find a destination matching the provided destination specifier:
{ id:B1234A5C-67B8-901D-B2CB-FE34F56BDE78 }
Ineligible destinations for the "Runner" scheme:
{ platform:iOS, id:dvtdevice-DVTiPhonePlaceholder-iphoneos:placeholder, name:Any iOS Device, error:iOS 17.0 is not installed. To use with Xcode, first download and install the platform }
```
Print a pretty error to make it easier for developers to know what to do.
Part 2 of https://github.com/flutter/flutter/issues/129558.
