JS: update tests

compiler/testData/codegen/box/binaryOp/overflowInt.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JS
-// reason - Int doesn't overflow in JS, TODO: include after KT-7733 is fixed
 fun box(): String {
     val i1: Int = Int.MAX_VALUE
     val i2 = i1 + 1

compiler/testData/codegen/box/intrinsics/kt12125.kt

@@ -1,6 +1,3 @@
-// TODO: muted automatically, investigate should it be ran for JS or not
-// IGNORE_BACKEND: JS
-
 fun test(i: Int): Int {
     return i
 }

compiler/testData/codegen/box/intrinsics/kt12125_inc.kt

@@ -1,6 +1,3 @@
-// TODO: muted automatically, investigate should it be ran for JS or not
-// IGNORE_BACKEND: JS
-
 fun test(i: Int): Int {
     return i
 }