CI: Try to reclaim a bit more concurrency (#2255)

Let's see if we can get CI running a little bit faster.

Author: smalis-msft

.config/nextest.toml

@@ -13,14 +13,14 @@ threads-required = 3
 # same profile
 filter = 'package(~vmm_tests) and test(openhcl)'
 # Mark OpenHCL VMM tests as extra heavy, as they have to also run VTL2.
-threads-required = 6
+threads-required = 5
 
 [[profile.default.overrides]]
 # use fuzzy-matching for the package() to allow out-of-tree tests to use the
 # same profile
 filter = 'package(~vmm_tests) and test(heavy) and not (test(very_heavy))'
 # Mark heavy tests as extra heavy, as they include up to 16 vps.
-threads-required = 24
+threads-required = 18
 
 [[profile.default.overrides]]
 # use fuzzy-matching for the package() to allow out-of-tree tests to use the