Add test cases for AST-65 (return before define)

test/fail/branch-before-define.as

@@ -0,0 +1,15 @@
+func f():() -> Int {
+  { label exit : (() -> Int) {
+      func g() : Int = x; // reference x
+      break exit (func() : Int{ g(); }); // early exit omits definition of x
+      let x:Int = 666;
+      func():Int{777;};
+    }
+  };
+};
+
+print "1\n";
+let h = f();
+
+print "2\n";
+let wrong = h();

test/fail/ok/branch-before-define.run-ir.ok

@@ -0,0 +1,3 @@
+1
+2
+branch-before-define.as:3.24-3.25: execution error, accessing identifier before its definition

test/fail/ok/branch-before-define.run-low.ok

@@ -0,0 +1,3 @@
+1
+2
+branch-before-define.as:3.24-3.25: execution error, accessing identifier before its definition

test/fail/ok/branch-before-define.run.ok

@@ -0,0 +1,3 @@
+1
+2
+branch-before-define.as:3.24-3.25: execution error, accessing identifier before its definition

test/fail/ok/branch-before-define.wasm-run.ok

@@ -0,0 +1 @@
+_out/branch-before-define.wasm:0x___: runtime trap: unreachable executed

test/fail/ok/return-before-define.run-ir.ok

@@ -0,0 +1,3 @@
+1
+2
+return-before-define.as:2.22-2.23: execution error, accessing identifier before its definition

test/fail/ok/return-before-define.run-low.ok

@@ -0,0 +1,3 @@
+1
+2
+return-before-define.as:2.22-2.23: execution error, accessing identifier before its definition

test/fail/ok/return-before-define.run.ok

@@ -0,0 +1,3 @@
+1
+2
+return-before-define.as:2.22-2.23: execution error, accessing identifier before its definition

test/fail/ok/return-before-define.wasm-run.ok

@@ -0,0 +1 @@
+_out/return-before-define.wasm:0x___: runtime trap: unreachable executed

test/fail/return-before-define.as

@@ -0,0 +1,13 @@
+func f():() -> Int {
+  { func g() : Int = x; // reference x
+    return (func() : Int{ g(); }); // early exit omits definition of x
+    let x:Int = 666;
+    func():Int{777;};
+  };
+};
+
+print "1\n";
+let h = f();
+
+print "2\n";
+let wrong = h();