patch 8.0.0452: some macros are in lower case

Problem:    Some macros are in lower case.
Solution:   Make a few more macros upper case.
diff --git a/src/regexp.c b/src/regexp.c
index 57f3423..91b8015 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -4523,14 +4523,14 @@
 	    break;
 
 	  case WHITE:
-	    if (!vim_iswhite(c))
+	    if (!VIM_ISWHITE(c))
 		status = RA_NOMATCH;
 	    else
 		ADVANCE_REGINPUT();
 	    break;
 
 	  case NWHITE:
-	    if (c == NUL || vim_iswhite(c))
+	    if (c == NUL || VIM_ISWHITE(c))
 		status = RA_NOMATCH;
 	    else
 		ADVANCE_REGINPUT();