patch 8.2.0287: Vim9: return in try block not tested; catch not tested

Problem:    Vim9: return in try block not tested; catch with pattern not
            tested.
Solution:   Add tests.  Make it work.
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 6fad391..7be8cdb 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -1065,6 +1065,7 @@
 		    trycmd->tcd_frame = ectx.ec_frame;
 		    trycmd->tcd_catch_idx = iptr->isn_arg.try.try_catch;
 		    trycmd->tcd_finally_idx = iptr->isn_arg.try.try_finally;
+		    trycmd->tcd_caught = FALSE;
 		}
 		break;
 
@@ -1109,7 +1110,7 @@
 			--trylevel;
 			trycmd = ((trycmd_T *)trystack->ga_data)
 							    + trystack->ga_len;
-			if (trycmd->tcd_caught)
+			if (trycmd->tcd_caught && current_exception != NULL)
 			{
 			    // discard the exception
 			    if (caught_stack == current_exception)