Circle CI: Cache Hermes dirs in iOS jobs (#33828)

Summary:
Avoid re-building Hermes if a cache hit is found for the required Hermes version.

Cache sdks/hermes and sdks/hermesc in Circle CI iOS jobs: `test_ios_rntester`, `build_ios`, and `test_ios`.

`test_ios_rntester` "Install CocoaPod Dependencies" step reduced from 37m40s to 3m35s.

`test_ios` "Generate RNTesterPods workspace" step reduced from 36m54s to 1m34s.

Pull Request resolved: https://github.com/facebook/react-native/pull/33828

Changelog: [Internal]

Reviewed By: cortinico

Differential Revision: D36365596

fbshipit-source-id: b5b6fe639f18b1724f80ab61c2262659c4987ff6

.circleci/config.yml

@@ -40,6 +40,7 @@ references:
     gems_cache_key: &gems_cache_key v1-gems-{{ checksum "Gemfile.lock" }}
     gradle_cache_key: &gradle_cache_key v1-gradle-{{ checksum "gradle/wrapper/gradle-wrapper.properties" }}-{{ checksum "ReactAndroid/gradle.properties" }}
     hermes_cache_key: &hermes_cache_key v1-hermes-{{ .Environment.CIRCLE_JOB }}-{{ checksum "/tmp/hermes/hermesversion" }}
+    hermes_sdk_cache_key: &hermes_sdk_cache_key v1-hermes-{{ .Environment.CIRCLE_JOB }}-{{ checksum "sdks/.hermesversion" }}
     hermes_windows_cache_key: &hermes_windows_cache_key v1-hermes-{{ .Environment.CIRCLE_JOB }}-{{ checksum "tmp/hermes/hermesversion" }}
     pods_cache_key: &pods_cache_key v6-pods-{{ .Environment.CIRCLE_JOB }}-{{ checksum "packages/rn-tester/Podfile.lock.bak" }}-{{ checksum "packages/rn-tester/Podfile" }}
     windows_yarn_cache_key: &windows_yarn_cache_key v1-win-yarn-cache-{{ arch }}-{{ checksum "yarn.lock" }}
@@ -251,6 +252,28 @@ commands:
           name: Report size of RNTester.app (analysis-bot)
           command: GITHUB_TOKEN="$PUBLIC_ANALYSISBOT_GITHUB_TOKEN_A""$PUBLIC_ANALYSISBOT_GITHUB_TOKEN_B" scripts/circleci/report-bundle-size.sh << parameters.platform >> || true
 
+  with_hermes_sdk_cache_span:
+    parameters:
+      steps:
+        type: steps
+    steps:
+      - run:
+          name: Setup Hermes cache
+          command: |
+            HERMES_VERSION_FILE="sdks/.hermesversion"
+            if [ ! -f "$HERMES_VERSION_FILE" ]; then
+              git ls-remote https://github.com/facebook/hermes main | cut -f 1 > $HERMES_VERSION_FILE
+            fi
+      - restore_cache:
+          keys:
+            - *hermes_sdk_cache_key
+      - steps: << parameters.steps >>
+      - save_cache:
+          key: *hermes_sdk_cache_key
+          paths:
+            - sdks/hermesc
+            - sdks/hermes
+
 # -------------------------
 #          JOBS
 # -------------------------
@@ -426,6 +449,8 @@ jobs:
           name: Setup the CocoaPods environment
           command: bundle exec pod setup
 
+      - with_hermes_sdk_cache_span:
+          steps:
             - with_rntester_pods_cache_span:
                 steps:
                   - run:
@@ -503,6 +528,8 @@ jobs:
           name: Setup the CocoaPods environment
           command: bundle exec pod setup
 
+      - with_hermes_sdk_cache_span:
+          steps:
             - with_rntester_pods_cache_span:
                 steps:
                   - run:
@@ -752,6 +779,8 @@ jobs:
       - brew_install:
           package: cmake
 
+      - with_hermes_sdk_cache_span:
+          steps:
             - run:
                 name: Install CocoaPods dependencies
                 command: |