[SLC] LazyAnnotationsBox: drop redundant synchronization

We can use less strict rule for produced annotations:
* Previously: the same annotations from `findAnnotation` and `annotations`
have the same identity
* Now: the same annotations from `findAnnotation` and `annotations`
are equals by 'equals'

^KT-56046

generators/analysis-api-generator/tests/org/jetbrains/kotlin/generators/tests/analysis/api/lightClasses.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -88,5 +88,11 @@ internal fun TestGroupSuite.generateSymbolLightClassesTests() {
                 model("equivalentTo", pattern = TestGeneratorUtil.KT)
             }
         }
+
+        run {
+            testClass<AbstractSymbolLightClassesAnnotationEqualityForSourceTest> {
+                model("annotationsEquality", pattern = TestGeneratorUtil.KT)
+            }
+        }
     }
 }