Explicitly set verbose flag for customer testing. (#96634)

dev/customer_testing/ci.bat

@@ -16,4 +16,4 @@ CD ..\customer_testing
 CMD /S /C "IF EXIST "..\..\bin\cache\pkg\tests\" RMDIR /S /Q ..\..\bin\cache\pkg\tests"
 git clone https://github.com/flutter/tests.git ..\..\bin\cache\pkg\tests
 FOR /F "usebackq tokens=*" %%a IN (`dart --enable-asserts ..\tools\bin\find_commit.dart ..\..\bin\cache\pkg\tests`) DO git -C ..\..\bin\cache\pkg\tests checkout %%a
-dart --enable-asserts run_tests.dart --skip-on-fetch-failure --skip-template ..\..\bin\cache\pkg\tests\registry\*.test
+dart --enable-asserts run_tests.dart --verbose --skip-on-fetch-failure --skip-template ..\..\bin\cache\pkg\tests\registry\*.test

dev/customer_testing/ci.sh

@@ -34,4 +34,4 @@ git clone https://github.com/flutter/tests.git ../../bin/cache/pkg/tests
 git -C ../../bin/cache/pkg/tests checkout `dart --enable-asserts ../tools/bin/find_commit.dart ../../bin/cache/pkg/tests`
 
 # Finally, run the tests.
-dart --enable-asserts run_tests.dart --skip-on-fetch-failure --skip-template ../../bin/cache/pkg/tests/registry/*.test
+dart --enable-asserts run_tests.dart --verbose --skip-on-fetch-failure --skip-template ../../bin/cache/pkg/tests/registry/*.test