patch 8.2.3573: cannot decide whether to skip test that fails with 64 bit

Problem:    Cannot decide whether to skip test that fails with 64 bit ints.
            (closes #9072)
Solution:   Add v:sizeofint, v:sizeoflong and v:sizeofpointer.  Improve the
            check for multiply overflow.
diff --git a/src/evalvars.c b/src/evalvars.c
index 08736dd..6851eef 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -150,6 +150,9 @@
     {VV_NAME("collate",		 VAR_STRING), VV_RO},
     {VV_NAME("exiting",		 VAR_SPECIAL), VV_RO},
     {VV_NAME("colornames",       VAR_DICT), VV_RO},
+    {VV_NAME("sizeofint",	 VAR_NUMBER), VV_RO},
+    {VV_NAME("sizeoflong",	 VAR_NUMBER), VV_RO},
+    {VV_NAME("sizeofpointer",	 VAR_NUMBER), VV_RO},
 };
 
 // shorthand
@@ -234,6 +237,9 @@
     set_vim_var_nr(VV_NUMBERMAX, VARNUM_MAX);
     set_vim_var_nr(VV_NUMBERMIN, VARNUM_MIN);
     set_vim_var_nr(VV_NUMBERSIZE, sizeof(varnumber_T) * 8);
+    set_vim_var_nr(VV_SIZEOFINT, sizeof(int));
+    set_vim_var_nr(VV_SIZEOFLONG, sizeof(long));
+    set_vim_var_nr(VV_SIZEOFPOINTER, sizeof(char *));
 
     set_vim_var_nr(VV_TYPE_NUMBER,  VAR_TYPE_NUMBER);
     set_vim_var_nr(VV_TYPE_STRING,  VAR_TYPE_STRING);