[clang] NFC: Preparation for merging code to emit target and target_clones resolvers.

This change modifies CodeGenModule::emitMultiVersionFunctions() in preparation
for a change that will merge support for emitting target_clones resolvers into
this function. This change mostly serves to isolate indentation changes from
later behavior modifying changes.

Reviewed By: erichkeane

Differential Revision: https://reviews.llvm.org/D122957