[dwarfdump] Prettyprint DW_AT_APPLE_property_attribute bitfield values.

This change depends on the ApplePropertyString helper that I sent spearately.
Not sure how you want this tested: as a tool test by adding a binary to dump, or as an llvm test starting from an IR file?

Reviewers: dblaikie, samsonov

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5689

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219507 91177308-0d34-0410-b5e6-96231b3b80d8

test/DebugInfo/Inputs/dwarfdump-objc.m

@@ -0,0 +1,16 @@
+// Compile with clang -g dwarfdump-objc.m -c -Wno-objc-root-class
+
+@interface NSObject {} @end
+
+
+@interface TestInterface
+@property (readonly) int ReadOnly;
+@property (assign) int Assign;
+@property (readwrite) int ReadWrite;
+@property (retain) NSObject *Retain;
+@property (copy) NSObject *Copy;
+@property (nonatomic) int NonAtomic;
+@end
+
+@implementation TestInterface
+@end