testament: generic N-fold batching: windows CI 37mn=>16m (#14823)

* testament: run CI faster thanks to batching
* move ta_in, tstdin into existing tosproc
* move ta_out,tafalse,texitcode,tstderr into existing tosproc
* joinable osproc
* move tstdout into existing tosproc
* spec: batchable; fix tests
* fixup

testament/specs.nim

@@ -8,6 +8,15 @@
 #
 
 import sequtils, parseutils, strutils, os, streams, parsecfg
+from hashes import hash
+
+type TestamentData* = ref object
+  # better to group globals under 1 object; could group the other ones here too
+  batchArg*: string
+  testamentNumBatch*: int
+  testamentBatch*: int
+
+let testamentData0* = TestamentData()
 
 var compilerPrefix* = findExe("nim")
 
@@ -68,11 +77,13 @@ type
     ccodeCheck*: string
     maxCodeSize*: int
     err*: TResultEnum
+    inCurrentBatch*: bool
     targets*: set[TTarget]
     matrix*: seq[string]
     nimout*: string
     parseErrors*: string # when the spec definition is invalid, this is not empty.
     unjoinable*: bool
+    unbatchable*: bool
     useValgrind*: bool
     timeout*: float # in seconds, fractions possible,
                     # but don't rely on much precision
@@ -138,6 +149,12 @@ proc addLine*(self: var string; a,b: string) =
 proc initSpec*(filename: string): TSpec =
   result.file = filename
 
+proc isCurrentBatch(testamentData: TestamentData, filename: string): bool =
+  if testamentData.testamentNumBatch != 0:
+    hash(filename) mod testamentData.testamentNumBatch == testamentData.testamentBatch
+  else:
+    true
+
 proc parseSpec*(filename: string): TSpec =
   result.file = filename
   let specStr = extractSpec(filename)
@@ -203,6 +220,8 @@ proc parseSpec*(filename: string): TSpec =
         result.action = actionReject
       of "nimout":
         result.nimout = e.value
+      of "batchable":
+        result.unbatchable = not parseCfgBool(e.value)
       of "joinable":
         result.unjoinable = not parseCfgBool(e.value)
       of "valgrind":
@@ -297,3 +316,7 @@ proc parseSpec*(filename: string): TSpec =
 
   if skips.anyIt(it in result.file):
     result.err = reDisabled
+
+  result.inCurrentBatch = isCurrentBatch(testamentData0, filename) or result.unbatchable
+  if not result.inCurrentBatch:
+    result.err = reDisabled