This reverts commit bfe9c598.

This reverts commit 31e33647.

This change updates the platform runners in the benchmarks subdir.

I've attempted to replace the entire group with new code as if the project were recreated with flutter create so that they don't become a Frankenstein of minor changes to make it work again, but just plain old generated code that can be replaced and updated in place.

The stocks example app is outdated and deprecated, but we still use it for some benchmark tests. Moving it into the benchmarks directory to indicate its status.

* Use Xcode build configurations to drive Flutter build mode

* Proper check wrt local_engine, print error if profile mode misisng

* Remove unused code, update tests, fix template problem, update warning

* fix up warning

* add explanatory dev comment

* fix whitespace

* missing words, change lambda arrow to function body

* error indentation

* Test early exits for xcode_backend.sh

* only on macOS, use right test

* Update error messages

* case insensitive compare for build config

* Update gallery podfile

* update projects to add profile configuration

* make compatible with flavors

* add missing plist files

* add FLUTTER_FRAMEWORK_DIR back, set swift version for profile, tell Podfile about profile

* Revert "Update templates (#23698)"

This reverts commit 5b0de6d6.

* Revert "Verify that date/number translations exist for all supported languages (#23692)"

This reverts commit 3449edf2.

* Revert "Reland Xcode backend refactor (#23574)"

This reverts commit 7270f284.

* Use Xcode build configurations to drive Flutter build mode

* Proper check wrt local_engine, print error if profile mode misisng

* Remove unused code, update tests, fix template problem, update warning

* fix up warning

* add explanatory dev comment

* fix whitespace

* missing words, change lambda arrow to function body

* error indentation

* Test early exits for xcode_backend.sh

* only on macOS, use right test

* Update error messages

* case insensitive compare for build config

* Update gallery podfile

* update projects to add profile configuration

* make compatible with flavors

* add missing plist files

This yak shave went as follows:

Fix https://github.com/flutter/flutter/issues/8795 by adding stocks to
the examples README.

Notice the layers entry in that README isn't quite right either.
Update that.

Check the layers/README file is worth pointing at.

Update the layers/README.

Let's run some of the layer tests to see if they still work.

Oops, need to update them to gradle.

Ok let's try running them again.

Oops, sector is broken.

Add a test for sector.

Fix sector. Find you need to add an assert to a const constructor.

Notice we need to turn const asserts on for the analyzer.

Notice the analysis_options files are out of sync with each other and
with the full list of lints.

Turn on the lints that should be on.

Fix the bugs that finds.

Update templates and example Xcode project files to indicate they've
been tested for Xcode 8.3 compatibility.

This prevents project re-validation on initial Xcode launch.