Add test cases from issue chapel-lang#19352

---
Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

test/modules/shadowing/issue-19352-1.chpl

@@ -0,0 +1,23 @@
+module Library {
+  record rec {
+    proc method() { writeln("Library's rec.method()"); }
+  }
+}
+
+
+module LibraryPlus {
+  import Library;
+  import Library.rec;
+
+  proc rec.method() { writeln("LibraryPlus's rec.method()"); }
+}
+
+// Case 1
+module Program {
+  import Library;
+  proc main() {
+    import LibraryPlus.rec; // does this make LibraryPlus.rec.method "closer" ?
+    var r = new Library.rec();
+    r.method(); // currently: ambiguity error
+  }
+}

test/modules/shadowing/issue-19352-1.good

@@ -0,0 +1,4 @@
+issue-19352-1.chpl:18: In function 'main':
+issue-19352-1.chpl:21: error: ambiguous call 'rec.method()'
+issue-19352-1.chpl:3: note: candidates are: rec.method()
+issue-19352-1.chpl:12: note:                 rec.method()

test/modules/shadowing/issue-19352-2a.chpl

@@ -0,0 +1,18 @@
+module Library {
+  record rec {
+    proc method() { writeln("Library's rec.method()"); }
+  }
+}
+
+// Case 2a
+module Program {
+  import Library;
+  import Library.rec; // Should this bring in the methods as if defined here?
+
+  proc rec.method() { writeln("Program's rec.method()"); }
+
+  proc main() {
+    var r = new Library.rec();
+    r.method(); // currently outputs: Program's rec.method()
+  }
+}

test/modules/shadowing/issue-19352-2a.good

@@ -0,0 +1,4 @@
+issue-19352-2a.chpl:14: In function 'main':
+issue-19352-2a.chpl:16: error: ambiguous call 'rec.method()'
+issue-19352-2a.chpl:3: note: candidates are: rec.method()
+issue-19352-2a.chpl:12: note:                 rec.method()

test/modules/shadowing/issue-19352-2b.chpl

@@ -0,0 +1,18 @@
+module Library {
+  record rec {
+    proc method() { writeln("Library's rec.method()"); }
+  }
+}
+
+// Case 2b
+module Program {
+  import Library; // Should this bring in the methods
+                  // on types defined in Library as if defined here?
+
+  proc (Library.rec).method() { writeln("Program's rec.method()"); }
+
+  proc main() {
+    var r = new Library.rec();
+    r.method(); // currently outputs: Program's rec.method()
+  }
+}

test/modules/shadowing/issue-19352-2b.good

@@ -0,0 +1,4 @@
+issue-19352-2b.chpl:14: In function 'main':
+issue-19352-2b.chpl:16: error: ambiguous call 'rec.method()'
+issue-19352-2b.chpl:3: note: candidates are: rec.method()
+issue-19352-2b.chpl:12: note:                 (Library.rec).method()

test/modules/shadowing/issue-19352-3.chpl

@@ -0,0 +1,26 @@
+module Library {
+  record rec {
+    proc method() { writeln("Library's rec.method()"); }
+  }
+}
+
+
+module LibraryPlus {
+  import Library;
+  import Library.rec;
+
+  proc rec.method() { writeln("LibraryPlus's rec.method()"); }
+}
+
+// Case 3
+module Program {
+  public import Library;
+  public use LibraryPlus; // should LibraryPlus.rec.method now shadow Library.rec.method?
+
+  proc main() {
+    var r = new Library.rec();
+    r.method(); // currently:
+                //  without PR #19306, ambiguity error
+                //  with PR #19306, outputs LibraryPlus's rec.method()
+  }
+}

test/modules/shadowing/issue-19352-3.good

@@ -0,0 +1,4 @@
+issue-19352-3.chpl:20: In function 'main':
+issue-19352-3.chpl:22: error: ambiguous call 'rec.method()'
+issue-19352-3.chpl:3: note: candidates are: rec.method()
+issue-19352-3.chpl:12: note:                 rec.method()