[ASTImporter] Add test for ObjCAtTryStmt/ObjCAtCatchStmt/ObjCAtThrowStmt

[teemperor]

Turns out, the clang-import-test actually allows passing clang args via -Xcc, so I probably will revert the lang options changes I did in the previous commits.

[teemperor]

test/Import/objc-try-catch/Inputs/F.m

10

We usually should create a expression here, but the ObjCMessageExpr isn't implemented yet, so this bit weird code has to do the job.

test/Import/objc-try-catch/Inputs/F.m

+@interface Exception
+@end
+@interface OtherException
+@end
+
+void f() {
+  @try {
+    Exception *e;
+    @throw e;
+  }
+  @catch (Exception *varname) {
+  }
+  @finally {
+  }
+
+  @try {
+  }
+  @catch (Exception *varname1) {
+    @throw;
+  }
+  @catch (OtherException *varname2) {
+  }
+
+  @try {
+  }
+  @finally {
+  }
+}

test/Import/objc-try-catch/test.m

+// RUN: clang-import-test -x objective-c++ -Xcc -fobjc-exceptions -dump-ast -import %S/Inputs/F.m -expression %s | FileCheck %s
+
+// CHECK: ObjCAtTryStmt
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: DeclStmt
+// CHECK-NEXT: VarDecl
+// CHECK-NEXT: ObjCAtThrowStmt
+// CHECK-NEXT: ImplicitCastExpr
+// CHECK-NEXT: DeclRefExpr
+// CHECK-NEXT: ObjCAtCatchStmt
+// CHECK-NEXT: VarDecl
+// CHECK-SAME: varname
+// CHECK-SAME: 'Exception *'
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: ObjCAtFinallyStmt
+// CHECK-NEXT: CompoundStmt
+
+// CHECK-NEXT: ObjCAtTryStmt
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: ObjCAtCatchStmt
+// CHECK-NEXT: VarDecl
+// CHECK-SAME: varname1
+// CHECK-SAME: 'Exception *'
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: ObjCAtThrowStmt
+// CHECK-NEXT: <<NULL>>
+// CHECK-NEXT: ObjCAtCatchStmt
+// CHECK-NEXT: VarDecl
+// CHECK-SAME: varname2
+// CHECK-SAME: 'OtherException *'
+// CHECK-NEXT: CompoundStmt
+
+// CHECK-NEXT: ObjCAtTryStmt
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: ObjCAtFinallyStmt
+// CHECK-NEXT: CompoundStmt
+
+void expr() {
+  f();
+}