follow up #19968; add more tests (#20396)

tests/stdlib/tsystem.nim

@@ -88,6 +88,66 @@ block:
 
   doAssert y.b == {}
 
+block:
+  type
+    X = object
+      a: string
+      b: int
+
+  var y = X(b: 1314)
+
+  reset(y)
+
+  doAssert y.b == 0
+
+block:
+  type
+    X = object
+      a: string
+      b: float
+
+  var y = X(b: 1314.521)
+
+  reset(y)
+
+  doAssert y.b == 0.0
+
+block:
+  type
+    X = object
+      a: string
+      b: string
+
+  var y = X(b: "1314")
+
+  reset(y)
+
+  doAssert y.b == ""
+
+block:
+  type
+    X = object
+      a: string
+      b: seq[int]
+
+  var y = X(b: @[1, 3])
+
+  reset(y)
+
+  doAssert y.b == @[]
+
+block:
+  type
+    X = object
+      a: string
+      b: tuple[a: int, b: string]
+
+  var y = X(b: (1, "cc"))
+
+  reset(y)
+
+  doAssert y.b == (0, "")
+
 block:
   type
     Color = enum