Repository: flutter
Issue: flutter run --no-build still builds the app
Labels: tool,a: build,has reproducible steps,P2,found in release: 3.3,found in release: 3.7,team-tool,triaged-tool

`flutter run --no-build` is actually building my iOS app, even though `build/ios/iphoneos/Runner.app` exists and (if I'm understanding the feature) it should be using that.

Note the "Compiling, linking and signing" below (ran with verbose, it really is recompiling):
```
$ flutter run --no-build  
Launching lib/main.dart on iPhone 6s in debug mode...
Found saved certificate choice "Apple Development: Jenn Magder (2867XHZLGW)". To clear, use "flutter config".
Signing iOS app for device deployment using developer identity: "Apple Development: Jenn Magder (2867XHZLGW)"
Running Xcode build...                                                  
 └─Compiling, linking and signing...                         8.1s
Xcode build done.                                           12.0s
Installing and launching...                                        12.7s
Waiting for iPhone 6s to report its views...                         5ms
Syncing files to device iPhone 6s...                                56ms
```
Feature introduced in https://github.com/flutter/flutter/pull/5301.
```
$ flutter doctor -v
[✓] Flutter (Channel master, 1.23.0-19.0.pre.108, on Mac OS X 10.15.7 19H2 darwin-x64, locale en-US)
    • Flutter version 1.23.0-19.0.pre.108 at /Users/m/Projects/flutter
    • Framework revision 03db9bf918 (3 hours ago), 2020-10-19 12:28:43 -0700
    • Engine revision d03b759d04
    • Dart version 2.11.0 (build 2.11.0-229.0.dev)

[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/m/Library/Android/sdk
    • Platform android-30, build-tools 29.0.2
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 12.0)
    • Xcode at /Users/m/Applications/Xcode-12.app/Contents/Developer
    • Xcode 12.0, Build version 12A7209
    • CocoaPods version 1.9.3

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 50.0.1
    • Dart plugin version 193.7547
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] VS Code (version 1.49.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.13.2

[✓] Connected device (5 available)
    • iPhone 6s (mobile)     • d83d5bc53967baa0ee18626ba87b6254b2ab5418 • ios            • iOS 13.7
    • iPhone 8 Plus (mobile) • A75CFA74-4CE0-469D-AADE-DE01EC6E31CA     • ios            • com.apple.CoreSimulator.SimRuntime.iOS-14-0 (simulator)
    • macOS (desktop)        • macos                                    • darwin-x64     • Mac OS X 10.15.7 19H2 darwin-x64
    • Web Server (web)       • web-server                               • web-javascript • Flutter Tools
    • Chrome (web)           • chrome                                   • web-javascript • Google Chrome 86.0.4240.80
```