Condense and summarize doctor output without --verbose (#14173)

* Flatten change out from lots of merges and temporary hacks for #7224

* Expand fakes to cover cases where doctor passes

* -v != --verbose

* Cosmetic touchups

* delint

* Clean up summary line, add a switch for review comments

* Review comments

* nit

* review comment

* review comments

ISSUE_TEMPLATE.md

diff --git a/ISSUE_TEMPLATE.md b/ISSUE_TEMPLATE.md
index 6fe7f35..7f88cd3 100644
--- a/ISSUE_TEMPLATE.md
+++ b/ISSUE_TEMPLATE.md
@@ -13,6 +13,6 @@
 
 ## Flutter Doctor
 
-Paste the output of running `flutter doctor` here.
+Paste the output of running `flutter doctor -v` here.
 
 > For more information about diagnosing and reporting Flutter bugs, please see [https://flutter.io/bug-reports/](https://flutter.io/bug-reports/).