Rework deparenthesize-like methods

- Extract private `deparenthesizeOnce` and repeat it until get the same expression

- Drop redundant parameter `deparenthesizeRecursively`

- Drop some usages of `safeDeparenthesize` in `deparenthesize`
  because even if `deparenthesize` returns null (i.e. something was not parsed)
  there is no sense in working with such expressions

Note, that `deparenthesize` now unwraps nested labels' declaration (see changes in testData),
but it seems to be reasonable

compiler/testData/diagnostics/tests/BreakContinue.kt

@@ -82,4 +82,15 @@ class C {
         }
         a<!UNSAFE_CALL!>.<!>compareTo("2")
     }
+
+    fun twoLabelsOnLoop() {
+        label1@ label2@ for (i in 1..100) {
+            if (i > 0) {
+                break@label1
+            }
+            else {
+                break@label2
+            }
+        }
+    }
 }

compiler/testData/diagnostics/tests/BreakContinue.txt

@@ -12,5 +12,6 @@ internal final class C {
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     internal final fun notContainsBreak(/*0*/ a: kotlin.String?, /*1*/ b: kotlin.String?): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    internal final fun twoLabelsOnLoop(): kotlin.Unit
     internal final fun unresolvedBreak(/*0*/ a: kotlin.String?, /*1*/ array: kotlin.Array<kotlin.Int>): kotlin.Unit
 }