tests: Add the 'vega_x86_tag' to testlib

This allows us to test ./build/VEGA_X86/gem5.opt targets.

Change-Id: I4d8309f928317d03b63e07e5ebb43de68cded9f2
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/59010
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
diff --git a/ext/testlib/configuration.py b/ext/testlib/configuration.py
index c6b02eb..fd47e3b 100644
--- a/ext/testlib/configuration.py
+++ b/ext/testlib/configuration.py
@@ -233,6 +233,7 @@
     constants.isa_tag_type = 'isa'
     constants.x86_tag = 'X86'
     constants.gcn3_x86_tag = 'GCN3_X86'
+    constants.vega_x86_tag = 'VEGA_X86'
     constants.sparc_tag = 'SPARC'
     constants.riscv_tag = 'RISCV'
     constants.arm_tag = 'ARM'
@@ -261,6 +262,7 @@
         constants.isa_tag_type : (
             constants.x86_tag,
             constants.gcn3_x86_tag,
+            constants.vega_x86_tag,
             constants.sparc_tag,
             constants.riscv_tag,
             constants.arm_tag,
@@ -291,6 +293,7 @@
         constants.arm_tag   : (constants.host_arm_tag,),
         constants.x86_tag   : (constants.host_x86_64_tag,),
         constants.gcn3_x86_tag : (constants.host_x86_64_tag,),
+        constants.vega_x86_tag : (constants.host_x86_64_tag,),
         constants.sparc_tag : (constants.host_x86_64_tag,),
         constants.riscv_tag : (constants.host_x86_64_tag,),
         constants.mips_tag  : (constants.host_x86_64_tag,),