Simplify test.

go/ql/integration-tests/all-platforms/go/resolve-build-environment/newer-go-needed/diagnostics.expected

@@ -1,31 +0,0 @@
-{
-  "location": {
-    "file": "go.mod"
-  },
-  "markdownMessage": "As of Go 1.21, toolchain versions [must use the 1.N.P syntax](https://go.dev/doc/toolchain#version).\n\n`1.22` in `go.mod` does not match this syntax and there is no additional `toolchain` directive, which may cause some `go` commands to fail.",
-  "severity": "warning",
-  "source": {
-    "extractorName": "go",
-    "id": "go/autobuilder/invalid-go-toolchain-version",
-    "name": "Invalid Go toolchain version"
-  },
-  "visibility": {
-    "cliSummaryTable": true,
-    "statusPage": true,
-    "telemetry": true
-  }
-}
-{
-  "markdownMessage": "A single `go.mod` file was found.\n\n`go.mod`",
-  "severity": "note",
-  "source": {
-    "extractorName": "go",
-    "id": "go/autobuilder/single-root-go-mod-found",
-    "name": "A single `go.mod` file was found in the root"
-  },
-  "visibility": {
-    "cliSummaryTable": false,
-    "statusPage": false,
-    "telemetry": true
-  }
-}

go/ql/integration-tests/all-platforms/go/resolve-build-environment/newer-go-needed/test.py

@@ -1,3 +1,6 @@
-def test(codeql, go, check_build_environment):
-    check_build_environment.env = {"GOTOOLCHAIN": "go1.21.0"}
-    codeql.database.create(source_root="src")
+import os
+
+
+def test(check_build_environment, go):
+    # the check for resolve build-environment runs after the test and will pick up this environment variable
+    os.environ["GOTOOLCHAIN"] = "go1.21.0"