[esan|cfrag] Create the cfrag struct array for the runtime

Summary:
Fills the cfrag struct variable with an array of struct information
variables.

Reviewers: aizatsky, bruening

Subscribers: bruening, kcc, vitalybuka, eugenis, llvm-commits, zhaoqin

Differential Revision: http://reviews.llvm.org/D20661

llvm-svn: 271547