Fixed iteration limit hit from execproc (#15723) [backport:1.2] [backport:1.4]

When calling procs from Nim in Nimscript you could hit the VM iteration limit even though the code is functioning properly. This resolves that by making the iteration limit reset eachtime you call a proc.

(cherry picked from commit a87617956f)

compiler/vm.nim

@@ -2078,6 +2078,7 @@ proc execute(c: PCtx, start: int): PNode =
   result = rawExecute(c, start, tos).regToNode
 
 proc execProc*(c: PCtx; sym: PSym; args: openArray[PNode]): PNode =
+  c.loopIterations = c.config.maxLoopIterationsVM
   if sym.kind in routineKinds:
     if sym.typ.len-1 != args.len:
       localError(c.config, sym.info,