[clang][DebugInfo][test] Convert Objective-C property test to check LLVM IR (llvm#165286)

There's a couple of tests like this.

This patch series renames these to something more descriptive and
adjusts the tests to check IR. Currently the tests check raw assembly
output (not even dwarfdump). Which most likely hid some bugs around
property debug-info.

Author: Michael137

clang/test/DebugInfo/ObjC/property-basic.m

@@ -0,0 +1,20 @@
+// Checks basic debug-info generation for property. Makes sure we
+// create a DIObjCProperty for the synthesized property.
+
+// RUN: %clang_cc1 -emit-llvm -debug-info-kind=limited %s -o - | FileCheck %s
+
+// CHECK: !DIObjCProperty(name: "p1"
+// CHECK-SAME:            attributes: 2316
+// CHECK-SAME:            type: ![[P1_TYPE:[0-9]+]]
+//
+// CHECK: ![[P1_TYPE]] = !DIBasicType(name: "int"
+
+@interface I1 {
+int p1;
+}
+@property int p1;
+@end
+
+@implementation I1
+@synthesize p1;
+@end