fixes #10456,#12928 issues when chaining templates to sortedByIt (#15734)

* update c_malloc's to csize_t 

fix for broken --os:ios

* I'm an idiot sorry

* Create talgorithm.nim

* workaround for #10456

I don't understand the intricacies of how lambdalifting and template expansions interact with lent, so i don't know how to fix the real problem, but this sidesteps whatever issue that is.

* working test, use typeof rather than auto

tests/stdlib/talgorithm.nim

@@ -0,0 +1,18 @@
+discard """
+  output:'''@["3", "2", "1"]
+  '''
+"""
+#12928,10456
+import sequtils, strutils, algorithm, json
+
+proc test() = 
+  try: 
+    let info = parseJson("""
+    {"a": ["1", "2", "3"]}
+    """)
+    let prefixes = info["a"].getElems().mapIt(it.getStr()).sortedByIt(it).reversed()
+    echo prefixes
+  except:
+    discard
+  
+test()