modula2: Add missing comments to M2CaseList.mod and add testcases

modula2: Add missing comments to M2CaseList.mod and add testcases

This patch adds procedure block comments to M2CaseList.mod, changes
date values to use unique digits and add a new test case.

gcc/m2/ChangeLog:

	* gm2-compiler/M2CaseList.mod (NewRanges): Add block
	comment.
	(NewSet): Add block comment.
	(DisplayRanges): Add block comment.
	(IncludeElement): Add block comment.
	(IncludeElements): Add block comment.
	(appendString): Add block comment.
	(appendEnum): Add block comment.
	(appendTree): Add block comment.
	(SubrangeErrors): Add block comment.

gcc/testsuite/ChangeLog:

	* gm2/switches/case/fail/subrangecase.mod: Replace 19
	with 17.
	* gm2/switches/case/fail/subrangecase2.mod: Ditto.
	* gm2/switches/case/fail/subrangecase3.mod: Ditto.
	* gm2/switches/case/fail/subrangecase4.mod: Ditto.
	* gm2/switches/case/pass/subrangecase.mod: Ditto.
	* gm2/switches/case/pass/subrangecase2.mod: Ditto.
	* gm2/switches/case/pass/subrangecase3.mod: Ditto.
	* gm2/switches/case/pass/subrangecase4.mod: Ditto.
	* gm2/switches/case/fail/calendar.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>