Fix curly_braces_in_flow_control_structures lint.

R=brianwilkerson@google.com, paulberry@google.com

Change-Id: I63cb372bf04f80182f873e2143971cb3cf1392fe
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/127447
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

Author: scheglov

pkg/analyzer/analysis_options.yaml

@@ -11,7 +11,6 @@ analyzer:
     # violations that need to be cleaned up. Each one can be cleaned up and
     # enabled according to the value provided.
     avoid_return_types_on_setters: ignore
-    curly_braces_in_flow_control_structures: ignore
     empty_catches: ignore
     prefer_iterable_wheretype: ignore
     # TODO(srawlins): At the time of writing, 230 violations in lib/. The fix

pkg/analyzer/lib/src/dart/analysis/crc32.dart

@@ -280,9 +280,10 @@ int getCrc32(List<int> array, [int crc = 0]) {
     crc = _CRC32_TABLE[(crc ^ array[ip++]) & 0xff] ^ (crc >> 8);
     len -= 8;
   }
-  if (len > 0)
+  if (len > 0) {
     do {
       crc = _CRC32_TABLE[(crc ^ array[ip++]) & 0xff] ^ (crc >> 8);
     } while (--len > 0);
+  }
   return crc ^ 0xffffffff;
 }

pkg/analyzer/lib/src/dart/element/member.dart

@@ -706,8 +706,9 @@ class MethodMember extends ExecutableMember implements MethodElement {
         var typeParameter = typeParameters[i];
         if (typeParameter is TypeParameterElementImpl) {
           typeParameter.appendTo(buffer);
-        } else
+        } else {
           (typeParameter as TypeParameterMember).appendTo(buffer);
+        }
       }
       buffer.write('>');
     }