libstdc++-v3/testsuite/.../year_month_day/3.cc, 4.cc: Cut down for simulators

These two long-running tests happened to fail for me when
run in parallel (nprocs - 1) compared to a serial run, for
target mmix on my laptop.  The runtime is 3m40s for 3.cc
before this change, and 0.9s afterwards.

	* testsuite/std/time/year_month_day/3.cc (test01): Add ifdeffery to
	limit the tested dates.  For simulators, pass start and end dates
	limiting the tested range to 100000 days, centered on days (0).
	* testsuite/std/time/year_month_day/4.cc: Ditto.

libstdc++-v3/testsuite/std/time/year_month_day/3.cc

 // { dg-do run { target c++20 } }
+// { dg-additional-options "-DSTART_DAY=-50000 -DEND_DAY=50000 -DSTART_YMD=1833y/February/8d" { target simulator } }
 
 // Copyright (C) 2021-2024 Free Software Foundation, Inc.
 //
@@ -50,11 +51,19 @@ void test01()
 {
   using namespace std::chrono;
 
+#ifdef START_DAY
+  auto n   = days{START_DAY};
+  auto ymd = START_YMD;
+  auto end_day = days{END_DAY};
+#else
   // [-12687428, 11248737] maps to [-32767y/January/1d, 32767y/December/31d]
 
   auto n   = days{-12687428};
   auto ymd = -32767y/January/1d;
-  while (n < days{11248737}) {
+  auto end_day = days{11248737};
+#endif
+
+  while (n < end_day) {
     VERIFY( year_month_day{sys_days{n}} == ymd );
     ++n;
     advance(ymd);

libstdc++-v3/testsuite/std/time/year_month_day/4.cc

 // { dg-do run { target c++20 } }
+// { dg-additional-options "-DSTART_DAY=-50000 -DSTART_YMD=1833y/February/8d -DEND_YMD=2106y/November/24d" { target simulator } }
 
 // Copyright (C) 2021-2024 Free Software Foundation, Inc.
 //
@@ -50,11 +51,18 @@ void test01()
 {
   using namespace std::chrono;
 
+#ifdef START_DAY
+  auto n   = days{START_DAY};
+  auto ymd = START_YMD;
+#else
   // [-32767y/January/1d, 32767y/December/31d] maps to [-12687428, 11248737]
 
   auto n   = days{-12687428};
   auto ymd = -32767y/January/1d;
-  while (ymd < 32767y/December/31d) {
+#define END_YMD 32767y/December/31d
+#endif
+
+  while (ymd < END_YMD) {
     VERIFY( static_cast<sys_days>(ymd) == sys_days{n} );
     ++n;
     advance(ymd);