[Build Kite][Code Coverage] Drop ftr_run_order.json (#151114)

## Summary 

As of last year we stopped supporting FTR configs
in the code coverage buildkite job.

While investigating a flaky test,
I noticed the file's presence in
the buildkite artifacts ui.

This pr drops that.

**Note to Reviewers:**
`.buildkite/scripts/steps/test/pick_test_group_run_order.sh` is
currently used in 4 places:

1. `.buildkite/pipelines/code_coverage/daily.yml` **this is where this
pr is concerned**
1. `.buildkite/pipelines/pull_request/base.yml`
1. `.buildkite/pipelines/on_merge.yml`
1. `.buildkite/pipelines/es_snapshots/verify.yml`

This change is small but this file is shared, so we've to keep this in
mind.

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

.buildkite/pipeline-utils/ci-stats/pick_test_group_run_order.ts

@@ -179,6 +179,15 @@ export async function pickTestGroupRunOrder() {
     throw new Error(`invalid FUNCTIONAL_MAX_MINUTES: ${process.env.FUNCTIONAL_MAX_MINUTES}`);
   }
 
+  /**
+   * This env variable corresponds to the env stanza within
+   * https://github.com/elastic/kibana/blob/bc2cb5dc613c3d455a5fed9c54450fd7e46ffd92/.buildkite/pipelines/code_coverage/daily.yml#L17
+   *
+   * It is a flag that signals the job for which test runners will be executed.
+   *
+   * For example in code coverage pipeline definition, it is "limited"
+   * to 'unit,integration'.  This means FTR tests will not be executed.
+   */
   const LIMIT_CONFIG_TYPE = process.env.LIMIT_CONFIG_TYPE
     ? process.env.LIMIT_CONFIG_TYPE.split(',')
         .map((t) => t.trim())
@@ -218,9 +227,10 @@ export async function pickTestGroupRunOrder() {
       : ['build'];
 
   const { defaultQueue, ftrConfigsByQueue } = getEnabledFtrConfigs(FTR_CONFIG_PATTERNS);
-  if (!LIMIT_CONFIG_TYPE.includes('functional')) {
-    ftrConfigsByQueue.clear();
-  }
+
+  const ftrConfigsIncluded = LIMIT_CONFIG_TYPE.includes('functional');
+
+  if (!ftrConfigsIncluded) ftrConfigsByQueue.clear();
 
   const jestUnitConfigs = LIMIT_CONFIG_TYPE.includes('unit')
     ? globby.sync(['**/jest.config.js', '!**/__fixtures__/**'], {
@@ -377,9 +387,11 @@ export async function pickTestGroupRunOrder() {
   Fs.writeFileSync('jest_run_order.json', JSON.stringify({ unit, integration }, null, 2));
   bk.uploadArtifacts('jest_run_order.json');
 
-  // write the config for functional steps to an artifact that can be used by the individual functional jobs
-  Fs.writeFileSync('ftr_run_order.json', JSON.stringify(ftrRunOrder, null, 2));
-  bk.uploadArtifacts('ftr_run_order.json');
+  if (ftrConfigsIncluded) {
+    // write the config for functional steps to an artifact that can be used by the individual functional jobs
+    Fs.writeFileSync('ftr_run_order.json', JSON.stringify(ftrRunOrder, null, 2));
+    bk.uploadArtifacts('ftr_run_order.json');
+  }
 
   // upload the step definitions to Buildkite
   bk.uploadSteps(

.buildkite/pipelines/code_coverage/daily.yml

@@ -13,7 +13,6 @@ steps:
       queue: kibana-default
     env:
       FTR_CONFIGS_DEPS: ''
-      #      LIMIT_CONFIG_TYPE: 'unit,functional,integration'
       LIMIT_CONFIG_TYPE: 'unit,integration'
       JEST_UNIT_SCRIPT: '.buildkite/scripts/steps/code_coverage/jest.sh'
       JEST_INTEGRATION_SCRIPT: '.buildkite/scripts/steps/code_coverage/jest_integration.sh'
@@ -25,6 +24,5 @@ steps:
     depends_on:
       - jest
       - jest-integration
-    #      - ftr-configs
     timeout_in_minutes: 30
     key: ingest

.buildkite/scripts/steps/code_coverage/node_scripts.sh

@@ -1,30 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-buildPlatformPlugins() {
-  echo "--- Build Platform Plugins"
-
-  NODE_OPTIONS=--max_old_space_size=14336 \
-    node scripts/build_kibana_platform_plugins \
-    --no-examples --test-plugins --workers 4
-}
-
-runFTRInstrumented() {
-  local ftrConfig=$1
-  echo "--- $ runFTRInstrumented against $ftrConfig"
-
-  NODE_OPTIONS=--max_old_space_size=16384 \
-    ./node_modules/.bin/nyc \
-    --nycrc-path ./src/dev/code_coverage/nyc_config/nyc.server.config.js \
-    node scripts/functional_tests \
-    --config="$ftrConfig" \
-    --exclude-tag "skipCoverage"
-}
-
-reportMergeFunctional() {
-  echo "--- Merging code coverage for FTR Configs"
-
-  NODE_OPTIONS=--max_old_space_size=16384 yarn nyc report \
-    --nycrc-path src/dev/code_coverage/nyc_config/nyc.functional.config.js --reporter json
-}