compilation cache: fixed recently introduced bug (lazy loading of bodies)

tests/rodfiles/tgeneric1.nim

@@ -0,0 +1,13 @@
+discard """
+  output: "abcd"
+"""
+
+import tables
+
+var x = initTable[int, string]()
+
+x[2] = "ab"
+x[5] = "cd"
+
+echo x[2], x[5]
+

tests/rodfiles/tgeneric2.nim

@@ -0,0 +1,13 @@
+discard """
+  output: "abef"
+"""
+
+import tables
+
+var x = initTable[int, string]()
+
+x[2] = "ab"
+x[5] = "ef"
+
+echo x[2], x[5]
+

tests/tester.nim

@@ -309,6 +309,10 @@ proc runRodFiles(r: var TResults, options: string) =
   test "bmethods2.nim"
   delNimCache()
   
+  # test generics:
+  test "tgeneric1.nim"
+  test "tgeneric2.nim"
+  delNimCache()
 
 proc compileRodFiles(r: var TResults, options: string) =
   template test(filename: expr): stmt =