patch 8.1.1195: Vim script debugger functionality needs cleanup

Problem:    Vim script debugger functionality needs cleanup.
Solution:   Move debugger code to a separate file.  Add more tests. (Yegappan
            Lakshmanan, closes #4285)
diff --git a/src/Make_dice.mak b/src/Make_dice.mak
index 5bad80b..93e960a 100644
--- a/src/Make_dice.mak
+++ b/src/Make_dice.mak
@@ -33,6 +33,7 @@
 	charset.c \
 	crypt.c \
 	crypt_zip.c \
+	debugger.c \
 	dict.c \
 	diff.c \
 	digraph.c \
@@ -93,6 +94,7 @@
 	o/charset.o \
 	o/crypt.o \
 	o/crypt_zip.o \
+	o/debugger.o \
 	o/dict.o \
 	o/diff.o \
 	o/digraph.o \
@@ -179,6 +181,8 @@
 
 o/crypt_zip.o:	crypt_zip.c  $(SYMS)
 
+o/debugger.o:	debugger.c  $(SYMS)
+
 o/dict.o:	dict.c	$(SYMS)
 
 o/diff.o:	diff.c	$(SYMS)