gccrs: add test case to show issue is fixed

gccrs: add test case to show issue is fixed

The original test case 1773 has been moved to a new issue 3242 which
is still open and test-case is skipped. The original issue in 1773 is
fixed so this will close out that issue

Fixes Rust-Gcc#1773

gcc/testsuite/ChangeLog:

	* rust/compile/issue-1773.rs: new test case
	* rust/compile/nr2/exclude: nr2 cant handle this
	* rust/compile/issue-3242.rs: old test ranamed to match issue.

Signed-off-by: Philip Herron <herron.philip@googlemail.com>