[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

analysis/symbol-light-classes/testData/annotationsEquality/TopLevelFunctionWithRegularAnnotation.kt

@@ -0,0 +1,10 @@
+// PSI: org.jetbrains.kotlin.light.classes.symbol.methods.SymbolLightSimpleMethod
+// EXPECTED: one.Anno
+// UNEXPECTED: one.Anno2
+
+package one
+
+annotation class Anno
+
+@Anno
+fun regul<caret>arFunction() {}