patch 9.1.0804: tests: no error check when setting global 'cc'

Problem:  tests: no error check when setting global 'cc'
Solution: also parse and check global 'cc' value (Milly)

closes: #15914

Signed-off-by: Milly <milly.ca@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/buffer.c b/src/buffer.c
index 90be301..5359527 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -214,7 +214,7 @@
 	enter_buffer(curbuf);
 #ifdef FEAT_SYN_HL
 	if (old_tw != curbuf->b_p_tw)
-	    check_colorcolumn(curwin);
+	    check_colorcolumn(NULL, curwin);
 #endif
 	return FAIL;
     }
@@ -1213,7 +1213,7 @@
 
 #ifdef FEAT_SYN_HL
 	    if (old_tw != curbuf->b_p_tw)
-		check_colorcolumn(curwin);
+		check_colorcolumn(NULL, curwin);
 #endif
 	}
 	// If "old_curbuf" is NULL we are in big trouble here...
@@ -1911,7 +1911,7 @@
 	    enter_buffer(buf);
 #ifdef FEAT_SYN_HL
 	if (old_tw != curbuf->b_p_tw)
-	    check_colorcolumn(curwin);
+	    check_colorcolumn(NULL, curwin);
 #endif
     }
 }