[JVM_IR] Use iinc for incrementing Int variables.

Fix line number generation for assignments where the right-hand
side of the assignment is not on the same line.

Fix line number generation for intrinsics functions where the
function is not on the same line as the last argument.

Be careful to not break stepping behavior with the iinc
optimizations.

compiler/testData/debug/stepping/iincStepping.kt

@@ -0,0 +1,47 @@
+//FILE: test.kt
+fun box() {
+    var i = 0
+    ++i
+    i += 1
+    i +=
+        1
+    i -= 1
+    i -=
+        1
+    i = i + 1
+    i =
+        i + 1
+    i =
+        i +
+            1
+}
+
+// IGNORE_BACKEND: JVM
+// The current backend has strange stepping behavior for assignments.
+// It generates the line number for the assignment first, and then
+// the evaluation of the right hand side with line numbers.
+// That leads to the line number with the assignment typically
+// not being hit at all as it has no instructions. Also, stepping
+// through the evaluation of the right hand side and then hitting
+// the line number for the actual assignment makes more sense as
+// that is the actual evaluation order.
+
+// LINENUMBERS
+// test.kt:3
+// test.kt:4
+// test.kt:5
+// test.kt:6
+// test.kt:7
+// test.kt:6
+// test.kt:8
+// test.kt:9
+// test.kt:10
+// test.kt:9
+// test.kt:11
+// test.kt:13
+// test.kt:12
+// test.kt:15
+// test.kt:16
+// test.kt:15
+// test.kt:14
+// test.kt:17