Expose 3.4-asan Ruby builds from ruby-dev-builder

**What does this PR do?**

This PR provides the final piece of the puzzle to fix #682: now that
ruby-dev-builder is building `3.4-asan` Rubies since
ruby/ruby-dev-builder#15, we can make them
available for use.

**Motivation:**

At Datadog, we're using ASan builds to check for issues
[in our library](https://github.com/datadog/dd-trace-rb),
and having a `3.4-asan` build improves the experience of having
these checks be a required CI step. Using the ASan builds built from
ruby-head means our CI could break because of unrelated issues/changes
from ruby-head.

**Additional Notes:**

`yarn` was trying really hard to update a bunch of things, which
generated A LOT of diff noise. I've manually pared them down just
to the actual changes related to adding the new variant so the
diff makes a bit more sense.

**How to test the change?**

I've already tested this in
https://github.com/DataDog/dd-trace-rb/actions/runs/13392865620/job/37696781848
and it seems to be working fine!

.github/workflows/test.yml

@@ -34,6 +34,7 @@ jobs:
         - { os: windows-2025, ruby: mswin }
         - { os: windows-2025, ruby: ucrt  }
         - { os: ubuntu-24.04, ruby: asan }
+        - { os: ubuntu-24.04, ruby: 3.4-asan }
         exclude:
         # https://github.com/ruby/setup-ruby/issues/496
         - { os: ubuntu-22.04, ruby: '2.2' }

README.md

@@ -26,6 +26,9 @@ This action currently supports these versions of MRI, JRuby and TruffleRuby:
 Native extensions are automatically compiled with AddressSanitizer when using `ruby-asan`.
 `ruby-asan` is currently only available on `ubuntu-24.04`.
 
+`ruby-3.4-asan` is similar to `ruby-asan` but built from the latest stable 3.4 release tag.
+Like `ruby-asan`, it's currently only available on `ubuntu-24.04`.
+
 Regarding Windows ruby master builds, `mingw` is a MSYS2/MinGW build, `head` & `ucrt` are MSYS2/UCRT64
 builds, and `mswin` is a MSVC/VS 2022 build.
 

common.js

@@ -66,7 +66,8 @@ export async function time(name, block) {
 }
 
 export function isHeadVersion(rubyVersion) {
-  return ['head', 'debug',  'mingw', 'mswin', 'ucrt', 'asan'].includes(rubyVersion)
+  // 3.4-asan counts as "head" because the version cannot be selected -- you can only get whatever's latest
+  return ['head', 'debug',  'mingw', 'mswin', 'ucrt', 'asan', '3.4-asan'].includes(rubyVersion)
 }
 
 export function isStableVersion(engine, rubyVersion) {

ruby-builder-versions.json

@@ -14,7 +14,7 @@
     "3.2.0-preview1", "3.2.0-preview2", "3.2.0-preview3", "3.2.0-rc1", "3.2.0", "3.2.1", "3.2.2", "3.2.3", "3.2.4", "3.2.5", "3.2.6", "3.2.7",
     "3.3.0-preview1", "3.3.0-preview2", "3.3.0-preview3", "3.3.0-rc1", "3.3.0", "3.3.1", "3.3.2", "3.3.3", "3.3.4", "3.3.5", "3.3.6", "3.3.7",
     "3.4.0-preview1", "3.4.0-preview2", "3.4.0-rc1", "3.4.0", "3.4.1", "3.4.2",
-    "head", "debug", "asan"
+    "head", "debug", "asan", "3.4-asan"
   ],
   "jruby": [
     "9.1.17.0",