Avoid excessive name pollution in test files

Test files are more polite regarding the use of globals when locals
would do, and when globals are necessary deleting them after use.

testes/vararg.lua

@@ -3,13 +3,13 @@
 
 print('testing vararg')
 
-function f(a, ...)
+local function f (a, ...)
   local x = {n = select('#', ...), ...}
   for i = 1, x.n do assert(a[i] == x[i]) end
   return x.n
 end
 
-function c12 (...)
+local function c12 (...)
   assert(arg == _G.arg)    -- no local 'arg'
   local x = {...}; x.n = #x
   local res = (x.n==2 and x[1] == 1 and x[2] == 2)
@@ -17,7 +17,7 @@ function c12 (...)
   return res, 2
 end
 
-function vararg (...) return {n = select('#', ...), ...} end
+local function vararg (...) return {n = select('#', ...), ...} end
 
 local call = function (f, args) return f(table.unpack(args, 1, args.n)) end
 
@@ -29,7 +29,7 @@ assert(vararg().n == 0)
 assert(vararg(nil, nil).n == 2)
 
 assert(c12(1,2)==55)
-a,b = assert(call(c12, {1,2}))
+local a,b = assert(call(c12, {1,2}))
 assert(a == 55 and b == 2)
 a = call(c12, {1,2;n=2})
 assert(a == 55 and b == 2)
@@ -49,7 +49,7 @@ function t:f (...) local arg = {...}; return self[...]+#arg end
 assert(t:f(1,4) == 3 and t:f(2) == 11)
 print('+')
 
-lim = 20
+local lim = 20
 local i, a = 1, {}
 while i <= lim do a[i] = i+0.3; i=i+1 end
 
@@ -59,7 +59,7 @@ function f(a, b, c, d, ...)
          more[lim-4] == lim+0.3 and not more[lim-3])
 end
 
-function g(a,b,c)
+local function g (a,b,c)
   assert(a == 1.3 and b == 2.3 and c == 3.3)
 end
 
@@ -76,7 +76,7 @@ print("+")
 
 -- new-style varargs
 
-function oneless (a, ...) return ... end
+local function oneless (a, ...) return ... end
 
 function f (n, a, ...)
   local b
@@ -99,8 +99,8 @@ assert(a==nil and b==nil and c==nil and d==nil and e==nil)
 
 
 -- varargs for main chunks
-f = load[[ return {...} ]]
-x = f(2,3)
+local f = load[[ return {...} ]]
+local x = f(2,3)
 assert(x[1] == 2 and x[2] == 3 and x[3] == undef)