build: make src cache smaller (#36351)

Co-authored-by: Samuel Attard <samuel.r.attard@gmail.com>

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Samuel Attard <samuel.r.attard@gmail.com>

.circleci/config/base.yml

@@ -873,12 +873,12 @@ step-touch-sync-done: &step-touch-sync-done
 step-maybe-restore-src-cache: &step-maybe-restore-src-cache
   restore_cache:
     keys:
-      - v15-src-cache-{{ checksum "src/electron/.depshash" }}
+      - v16-src-cache-{{ checksum "src/electron/.depshash" }}
     name: Restoring src cache
 step-maybe-restore-src-cache-marker: &step-maybe-restore-src-cache-marker
   restore_cache:
     keys:
-      - v15-src-cache-marker-{{ checksum "src/electron/.depshash" }}
+      - v16-src-cache-marker-{{ checksum "src/electron/.depshash" }}
     name: Restoring src cache marker
 
 # Restore exact or closest git cache based on the hash of DEPS and .circle-sync-done
@@ -955,13 +955,15 @@ step-minimize-workspace-size-from-checkout: &step-minimize-workspace-size-from-c
       rm -rf third_party/electron_node/deps/v8
       rm -rf chrome/test/data/xr/webvr_info
       rm -rf src/third_party/angle/third_party/VK-GL-CTS/src
+      rm -rf src/third_party/swift-toolchain
+      rm -rf src/third_party/swiftshader/tests/regres/testlists
 
 # Save the src cache based on the deps hash
 step-save-src-cache: &step-save-src-cache
   save_cache:
     paths:
       - /var/portal
-    key: v15-src-cache-{{ checksum "/var/portal/src/electron/.depshash" }}
+    key: v16-src-cache-{{ checksum "/var/portal/src/electron/.depshash" }}
     name: Persisting src cache
 step-make-src-cache-marker: &step-make-src-cache-marker
   run:
@@ -971,7 +973,7 @@ step-save-src-cache-marker: &step-save-src-cache-marker
   save_cache:
     paths:
       - .src-cache-marker
-    key: v15-src-cache-marker-{{ checksum "/var/portal/src/electron/.depshash" }}
+    key: v16-src-cache-marker-{{ checksum "/var/portal/src/electron/.depshash" }}
 
 step-maybe-early-exit-no-doc-change: &step-maybe-early-exit-no-doc-change
   run: