Fix test for JS

It seems JS prints doubles differently from Java, so avoid them in test check files.

Author: odersky

tests/run/drop-apply-optimization.check

@@ -1 +1 @@
-Map(0 -> 3.0, 1 -> 6.0, 2 -> 6.0)
+Map(0 -> 6, 1 -> 12, 2 -> 12)

tests/run/drop-apply-optimization.scala

@@ -10,7 +10,7 @@ class A:
     .groupMapReduce: (k, v) =>
       (k + 3) % 3
     .apply: (k, v) =>
-      v.toDouble
+      v * 2
     .apply: (x, y) =>
       x + y
   println(res)