Improve test data format for SMAP codegen tests

Instead of comments in a Kotlin source file, add a .smap with the contents of
the source mapping data (and possible comments)

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

@@ -6,7 +6,6 @@ inline fun call(crossinline init: () -> Unit) {
     return init()
 }
 //NO_CHECK_LAMBDA_INLINING
-//SMAP ABSENT
 
 // FILE: 2.kt
 
@@ -30,17 +29,20 @@ fun box(): String {
     return test()
 }
 
+// FILE: 1.smap
 
-//SMAP
-//lambdaOnCallSite.1.kt
-//Kotlin
-//*S Kotlin
-//*F
-//+ 1 lambdaOnCallSite.1.kt
-//LambdaOnCallSite_1Kt
-//+ 2 lambdaOnCallSite.2.kt
-//builders/LambdaOnCallSite_2Kt
-//*L
-//1#1,34:1
-//4#2:35
-//*E
+// FILE: 2.smap
+
+SMAP
+2.kt
+Kotlin
+*S Kotlin
+*F
++ 1 2.kt
+_2Kt
++ 2 1.kt
+builders/_1Kt
+*L
+1#1,23:1
+6#2:24
+*E