test: reduce some clear() calls

Use only a single clear() call in some test/functional/vimscript/ test
files whose test cases have very little side effect.

A downside of using a single clear() is that if a crash happens in one
test case, all following test cases in the same file will also fail, but
these functionalities and tests don't change very often.

test/functional/vimscript/json_functions_spec.lua

@@ -13,8 +13,8 @@ local NIL = vim.NIL
 local source = n.source
 
 describe('json_decode() function', function()
-  local restart = function(...)
-    clear(...)
+  setup(function()
+    clear()
     source([[
       language C
       function Eq(exp, act)
@@ -57,8 +57,7 @@ describe('json_decode() function', function()
         endif
       endfunction
     ]])
-  end
-  before_each(restart)
+  end)
 
   local speq = function(expected, actual_expr)
     eq(1, fn.EvalEq(expected, actual_expr))
@@ -627,7 +626,7 @@ describe('json_decode() function', function()
 end)
 
 describe('json_encode() function', function()
-  before_each(function()
+  setup(function()
     clear()
     command('language C')
   end)

test/functional/vimscript/minmax_functions_spec.lua

@@ -8,7 +8,7 @@ local clear = n.clear
 local fn = n.fn
 local pcall_err = t.pcall_err
 
-before_each(clear)
+setup(clear)
 for _, func in ipairs({ 'min', 'max' }) do
   describe(func .. '()', function()
     it('gives a single error message when multiple values failed conversions', function()

test/functional/vimscript/msgpack_functions_spec.lua

@@ -10,7 +10,7 @@ local exc_exec = n.exc_exec
 local is_os = t.is_os
 
 describe('msgpack*() functions', function()
-  before_each(clear)
+  setup(clear)
 
   local obj_test = function(msg, obj)
     it(msg, function()
@@ -415,7 +415,7 @@ local parse_eq = function(expect, list_arg)
 end
 
 describe('msgpackparse() function', function()
-  before_each(clear)
+  setup(clear)
 
   it('restores nil as v:null', function()
     parse_eq(eval('[v:null]'), { '\192' })
@@ -525,7 +525,7 @@ describe('msgpackparse() function', function()
   end)
 
   it('fails to parse a partial', function()
-    command('function T() dict\nendfunction')
+    command('function! T() dict\nendfunction')
     eq(
       'Vim(call):E899: Argument of msgpackparse() must be a List or Blob',
       exc_exec('call msgpackparse(function("T", [1, 2], {}))')
@@ -555,7 +555,7 @@ describe('msgpackparse() function', function()
 end)
 
 describe('msgpackdump() function', function()
-  before_each(clear)
+  setup(clear)
 
   local dump_eq = function(exp_list, arg_expr)
     eq(exp_list, eval('msgpackdump(' .. arg_expr .. ')'))
@@ -636,7 +636,7 @@ describe('msgpackdump() function', function()
   end)
 
   it('fails to dump a partial', function()
-    command('function T() dict\nendfunction')
+    command('function! T() dict\nendfunction')
     command('let Todump = function("T", [1, 2], {})')
     eq(
       'Vim(call):E5004: Error while dumping msgpackdump() argument, index 0, itself: attempt to dump function reference',
@@ -776,7 +776,7 @@ describe('msgpackdump() function', function()
   end)
 
   it('fails to dump a partial', function()
-    command('function T() dict\nendfunction')
+    command('function! T() dict\nendfunction')
     eq(
       'Vim(call):E686: Argument of msgpackdump() must be a List',
       exc_exec('call msgpackdump(function("T", [1, 2], {}))')

test/functional/vimscript/operators_spec.lua

@@ -6,7 +6,7 @@ local eval = n.eval
 local clear = n.clear
 
 describe('Division operator', function()
-  before_each(clear)
+  setup(clear)
 
   it('returns infinity on {positive}/0.0', function()
     eq("str2float('inf')", eval('string(1.0/0.0)'))

test/functional/vimscript/printf_spec.lua

@@ -9,7 +9,7 @@ local api = n.api
 local exc_exec = n.exc_exec
 
 describe('printf()', function()
-  before_each(clear)
+  setup(clear)
 
   it('works with zero and %b', function()
     eq('0', fn.printf('%lb', 0))

test/functional/vimscript/screenchar_spec.lua

@@ -32,7 +32,7 @@ end
 
 describe('screenchar() and family respect floating windows', function()
   local function with_ext_multigrid(multigrid)
-    before_each(function()
+    setup(function()
       clear()
       Screen.new(40, 7, { ext_multigrid = multigrid })
       -- These commands result into visible text `aabc`.

test/functional/vimscript/sort_spec.lua

@@ -11,7 +11,7 @@ local command = n.command
 local exc_exec = n.exc_exec
 local pcall_err = t.pcall_err
 
-before_each(clear)
+setup(clear)
 
 describe('sort()', function()
   it('errors out when sorting special values', function()

test/functional/vimscript/string_spec.lua

@@ -13,7 +13,7 @@ local NIL = vim.NIL
 local source = n.source
 
 describe('string() function', function()
-  before_each(clear)
+  setup(clear)
 
   describe('used to represent floating-point values', function()
     it('dumps NaN values', function()
@@ -103,7 +103,7 @@ describe('string() function', function()
   end)
 
   describe('used to represent funcrefs', function()
-    before_each(function()
+    setup(function()
       source([[
         function Test1()
         endfunction

test/functional/vimscript/uniq_spec.lua

@@ -7,7 +7,7 @@ local command = n.command
 local exc_exec = n.exc_exec
 local pcall_err = t.pcall_err
 
-before_each(clear)
+setup(clear)
 
 describe('uniq()', function()
   it('errors out when processing special values', function()