patch 8.2.5031: cannot easily run the benchmarks

Problem:    Cannot easily run the benchmarks.
Solution:   Have "make benchmark" in the src directory work.

src/Makefile

@@ -2245,8 +2245,11 @@ testgui:
 testtiny:
 	cd testdir; $(MAKE) -f Makefile tiny VIMPROG=../$(VIMTARGET) SCRIPTSOURCE=../$(SCRIPTSOURCE)
 
+# Run benchmarks.
 benchmark:
-	cd testdir; $(MAKE) -f Makefile benchmark VIMPROG=../$(VIMTARGET) SCRIPTSOURCE=../$(SCRIPTSOURCE)
+	cd testdir; \
+		$(MAKE) -f Makefile benchmarkclean; \
+		$(MAKE) -f Makefile benchmark VIMPROG=../$(VIMTARGET) SCRIPTSOURCE=../$(SCRIPTSOURCE)
 
 unittesttargets:
 	$(MAKE) -f Makefile $(UNITTEST_TARGETS)

src/testdir/Makefile

@@ -90,6 +90,10 @@ clean:
 	-rm -f valgrind.*
 	-rm -f asan.*
 
+# Delete the files produced by benchmarking, so they can run again.
+benchmarkclean:
+	rm -f $(SCRIPTS_BENCH)
+
 nolog:
 	-rm -f test.log test_result.log messages
 

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    5031,
 /**/
     5030,
 /**/