backend: Don't create a Progression objects in 'for' loops

This patch optimizes the following pattern:

for (i in first..last step st) { ... }

In this case we need to create a Progression object and then call its
iterator() method causing at least 2 allocation per loop. This change
replaces such loops with the following constuction:

var inductionVar = first
checkProgressionStep(step)  // check if step > 0
last = getProgressionLastElement(first, last, step)
if (first <= last) {
    do {
        i = inductionVar
        inductionVar += step
        ...
    } while(i != last)
}

runtime/src/main/kotlin/konan/internal/RuntimeUtils.kt

@@ -16,6 +16,8 @@
 
 package konan.internal
 
+import kotlin.internal.getProgressionLastElement
+
 @ExportForCppRuntime
 fun ThrowNullPointerException(): Nothing {
     throw NullPointerException()
@@ -84,4 +86,13 @@ fun <T: Enum<T>> valuesForEnum(values: Array<T>): Array<T>
         result[value.ordinal] = value
     @Suppress("UNCHECKED_CAST")
     return result as Array<T>
-}
+}
+
+fun checkProgressionStep(step: Int)  = if (step > 0) step else throw IllegalArgumentException("Step must be positive, was: $step.")
+fun checkProgressionStep(step: Long) = if (step > 0) step else throw IllegalArgumentException("Step must be positive, was: $step.")
+
+fun getProgressionBound(start: Char, end: Char, step: Int): Char =
+        getProgressionBound(start.toInt(), end.toInt(), step).toChar()
+
+fun getProgressionBound(start: Int, end: Int, step: Int): Int = getProgressionLastElement(start, end, step)
+fun getProgressionBound(start: Long, end: Long, step: Long): Long = getProgressionLastElement(start, end, step)