Changes

[VE] Support register aliases in llvm-mc

Support register aliases in MC layer to compile existing assembly
files with clang and integrated assembler.

Reviewed By: simoll

Differential Revision: https://reviews.llvm.org/D90383

[VE] Add missing symbolic branch patterns

Add missing symbolic branch patterns to a regression test.

Reviewed By: simoll

Differential Revision: https://reviews.llvm.org/D90388

[zorg][PowerPC] Add tags for builders

Add the tag for all PowerPC builders so that we can identify them
easily.
eg: Check all with http://lab.llvm.org:8011/#/waterfall?tags=%20ppc

Reviewed By: gkistanova

Differential Revision: https://reviews.llvm.org/D90263