Refactor LLVM initialization code
Refactor LLVM initialization code

Change-Id: Ie944a14c1d4ae30d7e30f84408c598c9e021ea66
Reviewed-on: https://swiftshader-review.googlesource.com/20471
Tested-by: Logan Chien <54d97d247ead2e88f9d88f287e98620efa682c55@google.com>
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>

bkaradzic/SwiftShader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader