Merge pull request scala-js#4618 from catap/missed-bn

Add missed `/` for `js.BigInt`

Author: gzm0

library/src/main/scala/scala/scalajs/js/BigInt.scala

@@ -31,6 +31,7 @@ final class BigInt private[this] () extends js.Object {
 
   def +(other: BigInt): BigInt = js.native
   def *(other: BigInt): BigInt = js.native
+  def /(other: BigInt): BigInt = js.native
   def -(other: BigInt): BigInt = js.native
   def %(other: BigInt): BigInt = js.native
 

test-suite/js/src/test/scala/org/scalajs/testsuite/library/BigIntTest.scala

@@ -74,6 +74,9 @@ class BigIntTest {
     val multi = previousMaxSafe * js.BigInt(2)
     assertEquals(multi, js.BigInt("18014398509481982"))
 
+    val div = previousMaxSafe / js.BigInt(2)
+    assertEquals(div, js.BigInt("4503599627370495"))
+
     val subtr = multi - js.BigInt(10)
     assertEquals(subtr, js.BigInt("18014398509481972"))