Fixes #5062 (#5527); JS: holes in enums

tests/js/tbasicenum.nim

@@ -0,0 +1,10 @@
+discard """
+  output: "ABCDC"
+"""
+
+type
+  MyEnum = enum
+    A,B,C,D
+# trick the optimizer with an seq:
+var x = @[A,B,C,D]
+echo x[0],x[1],x[2],x[3],MyEnum(2)

tests/js/tenumhole.nim

@@ -0,0 +1,12 @@
+discard """
+  output: "first0second32third64"
+"""
+
+type Holed = enum
+  hFirst = (0,"first")
+  hSecond = (32,"second")
+  hThird = (64,"third")
+  
+var x = @[0,32,64] # This is just to avoid the compiler inlining the value of the enum
+
+echo Holed(x[0]),ord Holed(x[0]),Holed(x[1]),ord Holed(x[1]),Holed(x[2]),ord Holed(x[2])

tests/js/tenumnegkey.nim

@@ -0,0 +1,12 @@
+discard """
+  output: "first-12second32third64"
+"""
+
+type Holed = enum
+  hFirst = (-12,"first")
+  hSecond = (32,"second")
+  hThird = (64,"third")
+  
+var x = @[-12,32,64] # This is just to avoid the compiler inlining the value of the enum
+
+echo Holed(x[0]),ord Holed(x[0]),Holed(x[1]),ord Holed(x[1]),Holed(x[2]),ord Holed(x[2])

tests/js/tenumoffset.nim

@@ -0,0 +1,19 @@
+discard """
+  output: "my value A1my value Bconc2valueCabc4abc"
+"""
+
+const
+  strValB = "my value B"
+
+type
+  TMyEnum = enum
+    valueA = (1, "my value A"),
+    valueB = strValB & "conc",
+    valueC,
+    valueD = (4, "abc")
+
+proc getValue(i:int): TMyEnum = TMyEnum(i)
+
+# trick the optimizer with a variable:
+var x = getValue(4)
+echo getValue(1), ord(valueA), getValue(2), ord(valueB), getValue(3), getValue(4), ord(valueD), x