IR: cleanup expression implementations

Remove unused constructors with descriptors, minimize usages of
secondary constructors and make some properties non-lateinit, fix some
inspections.

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/FinallyBlocksLowering.kt

@@ -220,12 +220,13 @@ class FinallyBlocksLowering(val context: CommonBackendContext, private val throw
                 endOffset = endOffset,
                 type = context.irBuiltIns.unitType
             ).apply {
-                this.catches += irCatch(catchParameter).apply {
-                    result = irComposite {
+                this.catches += irCatch(
+                    catchParameter,
+                    irComposite {
                         +finallyExpression.copy()
                         +irThrow(irGet(catchParameter))
                     }
-                }
+                )
 
                 this.finallyExpression = null
             }

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LowerUtils.kt

@@ -111,11 +111,8 @@ fun IrBuilderWithScope.irNot(arg: IrExpression) =
 fun IrBuilderWithScope.irThrow(arg: IrExpression) =
     IrThrowImpl(startOffset, endOffset, context.irBuiltIns.nothingType, arg)
 
-fun IrBuilderWithScope.irCatch(catchParameter: IrVariable) =
-    IrCatchImpl(
-        startOffset, endOffset,
-        catchParameter
-    )
+fun IrBuilderWithScope.irCatch(catchParameter: IrVariable, result: IrExpression): IrCatch =
+    IrCatchImpl(startOffset, endOffset, catchParameter, result)
 
 fun IrBuilderWithScope.irImplicitCoercionToUnit(arg: IrExpression) =
     IrTypeOperatorCallImpl(