Fix range-based 'for' loop with 'continue' in range bounds

1. Search for increment function in range element type, not in inferred
induction variable type
(which can be inappropriate, e.g., 'Nothing' in case of 'continue').

2. Handle nested loops with shared exit labels
(generated by JVM_IR for KT-37370 case).

KT-37370 KT-37373

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

@@ -73,8 +73,12 @@ internal abstract class NumericForLoopHeader<T : NumericHeaderInfo>(
         // Always copy `lastExpression` is it may be used in multiple conditions.
         get() = field.deepCopyWithSymbols()
 
+    private val elementType: IrType
+
     init {
         with(builder) {
+            elementType = headerInfo.progressionType.elementType(context.irBuiltIns)
+
             // For this loop:
             //
             //   for (i in first()..last() step step())
@@ -86,7 +90,7 @@ internal abstract class NumericForLoopHeader<T : NumericHeaderInfo>(
             // LongProgression so last() should be cast to a Long.
             inductionVariable = scope.createTemporaryVariable(
                 headerInfo.first.castIfNecessary(
-                    headerInfo.progressionType.elementType(context.irBuiltIns),
+                    elementType,
                     headerInfo.progressionType.elementCastFunctionName
                 ),
                 nameHint = "inductionVariable",
@@ -99,7 +103,7 @@ internal abstract class NumericForLoopHeader<T : NumericHeaderInfo>(
             // TODO: Confirm if casting to non-nullable is still necessary
             val last = ensureNotNullable(
                 headerInfo.last.castIfNecessary(
-                    headerInfo.progressionType.elementType(context.irBuiltIns),
+                    elementType,
                     headerInfo.progressionType.elementCastFunctionName
                 )
             )
@@ -138,7 +142,7 @@ internal abstract class NumericForLoopHeader<T : NumericHeaderInfo>(
     /** Statement used to increment the induction variable. */
     protected fun incrementInductionVariable(builder: DeclarationIrBuilder): IrStatement = with(builder) {
         // inductionVariable = inductionVariable + step
-        val plusFun = inductionVariable.type.getClass()!!.functions.single {
+        val plusFun = elementType.getClass()!!.functions.single {
             it.name == OperatorNameConventions.PLUS &&
                     it.valueParameters.size == 1 &&
                     it.valueParameters[0].type == stepVariable.type