JVM: fix SMAP range extension logic

If `mapLineNumber` was called in non-monotonic order, e.g. N then N+2
then N+1, the first two calls created a range that spans [N; N+2] but
the third call did not reuse it.

compiler/testData/codegen/boxInline/smap/smap.kt

@@ -80,40 +80,36 @@ _2Kt
 builders/_1Kt
 *L
 1#1,25:1
-7#1,3:40
-10#1:45
-11#1,2:49
-13#1:52
-15#1:54
+7#1,3:36
+10#1:41
+11#1,2:45
+13#1:48
+15#1:50
 19#2:26
 7#2,9:27
-11#2,3:36
-8#2:39
-19#2:43
-7#2:44
-15#2:46
-11#2,2:47
-13#2:51
-8#2:53
+19#2:39
+7#2:40
+15#2:42
+11#2,2:43
+13#2:47
+8#2:49
 *E
 *S KotlinDebug
 *F
 + 1 2.kt
 _2Kt
 *L
-20#1,3:40
-20#1:45
-20#1,2:49
-20#1:52
-20#1:54
+20#1,3:36
+20#1:41
+20#1,2:45
+20#1:48
+20#1:50
 9#1:26
 9#1,9:27
-9#1,3:36
-9#1:39
-20#1:43
-20#1:44
-20#1:46
-20#1,2:47
-20#1:51
-20#1:53
+20#1:39
+20#1:40
+20#1:42
+20#1,2:43
+20#1:47
+20#1:49
 *E