Support for llvm-bcanalyzer dumping of record array strings.

Summary:
Adds support for automatically detecting and printing strings
represented by Array abbrev operands, analogous to the string dumping
performed for Blob abbrev operands.

Enhanced the ThinLTO combined index test to check for the appropriate
module and function strings.

Reviewers: dexonsmith, joker.eph, davidxl

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13553

llvm-svn: 249695