Update makefile colorize tests according to the latest grammar. (#61961)

1. Handling the '!=' variable assignment operator.
2. Handling the "#" (hashtag) in the quotes inside the recipe.
3. Restore the recipe handling.

Issue: #60030, #61475

extensions/make/test/colorize-fixtures/makefile

@@ -25,10 +25,16 @@ hello.o: hello.cpp \
 clean:
 	rm *o hello
 
+.PHONY: all
 all:
 	# "$$" in a shell means to escape makefile's variable substitution.
 	some_shell_var=$$(sed -nre 's/some regex with (group)/\1/p')
 
+.PHONY: echo
+echo:
+	echo "#" and '#' in quotes are not comments \
+		and '\' will be continued
+
 define defined
   $(info Checking existance of $(1) $(flavor $(1)))
   $(if $(filter undefined,$(flavor $(1))),0,1)
@@ -54,3 +60,14 @@ ifeq ("${ok}", "skip")
   $(ok))}
   ${ok}})
 endif
+
+result != echo "'$(ok)' $(shell echo "from inlined shell")"
+$(info $(result))
+
+# Below is a test of variable assignment without any spacing.
+var=val
+var?=val
+var:=123
+var!=echo val
+var:=val \
+notvar=butval