[VE] Support VE architecture

Summary:
Modify LNT to let it know VE architecture in order to run
llvm-test-suite well on NEC SX-Aurora VE architecture.

Reviewed By: kristof.beyls

Differential Revision: https://reviews.llvm.org/D76334

Author: kaz7

lnt/tests/nt.py

@@ -424,6 +424,8 @@ def compute_run_make_variables(self):
                 llvm_arch = 'Sparc'
             elif arch in ('mips', 'mipsel', 'mips64', 'mips64el'):
                 llvm_arch = 'Mips'
+            elif arch in ('ve'):
+                llvm_arch = 'VE'
 
         if llvm_arch is not None:
             make_variables['ARCH'] = llvm_arch