Enhance fuzzershell.c to read and execute SQL commands in the autoexec table

of the database under test.  Add the dbfuzz.c test program combining selected
features of fuzzershell.c and fuzzcheck.c.

FossilOrigin-Name: ef6e071a62cd79a0edbbef9f41ca9482540e5cb8

main.mk

@@ -477,6 +477,7 @@ SHELL_OPT += -DSQLITE_ENABLE_EXPLAIN_COMMENTS
 SHELL_OPT += -DSQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
 FUZZERSHELL_OPT = -DSQLITE_ENABLE_JSON1
 FUZZCHECK_OPT = -DSQLITE_ENABLE_JSON1 -DSQLITE_ENABLE_MEMSYS5
+DBFUZZ_OPT =
 
 # This is the default Makefile target.  The objects listed here
 # are what get build when you type just "make" with no arguments.
@@ -513,6 +514,11 @@ fuzzershell$(EXE):	$(TOP)/tool/fuzzershell.c sqlite3.c sqlite3.h
 	  $(FUZZERSHELL_OPT) $(TOP)/tool/fuzzershell.c sqlite3.c \
 	  $(TLIBS) $(THREADLIB)
 
+dbfuzz$(EXE):	$(TOP)/test/dbfuzz.c sqlite3.c sqlite3.h
+	$(TCCX) -o dbfuzz$(EXE) -DSQLITE_THREADSAFE=0 -DSQLITE_OMIT_LOAD_EXTENSION \
+	  $(DBFUZZ_OPT) $(TOP)/test/dbfuzz.c sqlite3.c \
+	  $(TLIBS) $(THREADLIB)
+
 fuzzcheck$(EXE):	$(TOP)/test/fuzzcheck.c sqlite3.c sqlite3.h $(TOP)/test/ossfuzz.c
 	$(TCCX) -o fuzzcheck$(EXE) -DSQLITE_THREADSAFE=0 -DSQLITE_OMIT_LOAD_EXTENSION \
 		-DSQLITE_ENABLE_MEMSYS5 $(FUZZCHECK_OPT) -DSQLITE_OSS_FUZZ \