[analysis_server] Add test that convert_to_expression_body doesn't show for primary constructor bodies

Fixes https://github.com/dart-lang/sdk/issues/63042

Change-Id: Ib6402b03b9a5854e9fd33332ed6b32e966c192bb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/493140
Reviewed-by: Keerti Parthasarathy <keertip@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Keerti Parthasarathy <keertip@google.com>

pkg/analysis_server/test/src/services/correction/assist/convert_into_expression_body_test.dart

@@ -294,6 +294,24 @@ var ^V = 42;
     await assertNoAssist();
   }
 
+  Future<void> test_primaryConstructorBody_brace() async {
+    await resolveTestCode('''
+class A() {
+  this ^{}
+}
+''');
+    await assertNoAssist();
+  }
+
+  Future<void> test_primaryConstructorBody_keyword() async {
+    await resolveTestCode('''
+class A() {
+  ^this {}
+}
+''');
+    await assertNoAssist();
+  }
+
   Future<void> test_topFunction_onReturnStatement() async {
     await resolveTestCode('''
 fff() {