CI: Adjust job parallelism to actually match available resources

- Some jobs don't actually run in parallel but have the `parallelism` setting enabled.
- `soltest_all` could be parallelized much more.

.circleci/config.yml

@@ -695,7 +695,6 @@ jobs:
 
   t_ubu_codecov:
     <<: *base_ubuntu2004
-    parallelism: 6
     environment:
       EVM: << pipeline.parameters.evm-version >>
       OPTIMIZE: 1
@@ -878,7 +877,7 @@ jobs:
 
   t_ubu_soltest_all: &t_ubu_soltest_all
     <<: *base_ubuntu2004
-    parallelism: 6
+    parallelism: 15 # 7 EVM versions, each with/without optimization + 1 ABIv1/@nooptions run
     <<: *steps_soltest_all
 
   t_archlinux_soltest: &t_archlinux_soltest
@@ -937,7 +936,6 @@ jobs:
 
   t_ubu_asan_soltest:
     <<: *base_ubuntu2004
-    parallelism: 6
     environment:
       EVM: << pipeline.parameters.evm-version >>
       OPTIMIZE: 0

.circleci/soltest_all.sh

@@ -31,6 +31,7 @@ REPODIR="$(realpath "$(dirname "$0")"/..)"
 # shellcheck source=scripts/common.sh
 source "${REPODIR}/scripts/common.sh"
 
+# NOTE: If you add/remove values, remember to update `parallelism` setting in CircleCI config.
 EVM_VALUES=(homestead byzantium constantinople petersburg istanbul berlin london)
 DEFAULT_EVM=london
 [[ " ${EVM_VALUES[*]} " =~ $DEFAULT_EVM ]]