Update analysis options files.

Change-Id: I06b659b5ee7105d3f11343259f787194f1d2bd79
Reviewed-on: https://dart-review.googlesource.com/63501
Reviewed-by: Phil Quitslund <pquitslund@google.com>
Commit-Queue: Devon Carew <devoncarew@google.com>

pkg/analysis_server/analysis_options.yaml

@@ -1,5 +1,3 @@
-analyzer:
-  strong-mode: true
 linter:
   rules:
     - empty_constructor_bodies

pkg/analyzer/analysis_options.yaml

@@ -1,5 +1,3 @@
-analyzer:
-  strong-mode: true
 linter:
   rules:
     - empty_constructor_bodies

pkg/analyzer_cli/analysis_options.yaml

@@ -1,5 +1,4 @@
 analyzer:
-  strong-mode: true
   exclude:
     - 'test/data'
 linter:

pkg/analyzer_plugin/analysis_options.yaml

@@ -1,5 +1,3 @@
-analyzer:
-  strong-mode: true
 linter:
   rules:
     - annotate_overrides

pkg/front_end/analysis_options.yaml

@@ -3,7 +3,6 @@
 # BSD-style license that can be found in the LICENSE file.
 
 analyzer:
-  strong-mode: true
   language:
     enableSuperMixins: false
   exclude:

pkg/kernel/analysis_options.yaml

@@ -1,5 +1,4 @@
 analyzer:
-  strong-mode: true
   language:
     enableSuperMixins: false
   exclude:

pkg/meta/analysis_options.yaml

@@ -1,2 +0,0 @@
-analyzer:
-  strong-mode: true