Auto merge of #20085 - servo:jdm-patch-2, r=emilio

Clean target directories of linux builders.

This should avoid our frequent problems with running out of disk space on the smallest linux build machines. This linux builders are also our fastest ones, so it shouldn't slow down our CI too much.

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etc/ci/buildbot_steps.yml

@@ -79,12 +79,14 @@ mac-nightly:
 linux-rel-intermittent:
   - ./mach clean-nightlies --keep 3 --force
   - ./mach clean-cargo-cache --keep 3 --force
+  - ./mach clean
   - ./mach build --release
   - ./etc/ci/check_intermittents.sh --log-raw intermittents.log
 
 linux-rel-nogate:
   - ./mach clean-nightlies --keep 3 --force
   - ./mach clean-cargo-cache --keep 3 --force
+  - ./mach clean
   - ./mach build --release
   - python ./etc/ci/chaos_monkey_test.py
   - env RUSTFLAGS= bash ./etc/ci/mutation_test.sh
@@ -102,6 +104,7 @@ linux-dev:
   commands:
     - ./mach clean-nightlies --keep 3 --force
     - ./mach clean-cargo-cache --keep 3 --force
+    - ./mach clean
     - ./mach test-tidy --no-progress --all
     - ./mach test-tidy --no-progress --self-test
     - ./mach build --dev
@@ -121,6 +124,7 @@ linux-rel-wpt:
   commands:
     - ./mach clean-nightlies --keep 3 --force
     - ./mach clean-cargo-cache --keep 3 --force
+    - ./mach clean
     - ./mach build --release --with-debug-assertions
     - ./mach test-wpt-failure
     - ./mach test-wpt --release --processes 24 --total-chunks 2 --this-chunk 1 --log-raw test-wpt.log --log-errorsummary wpt-errorsummary.log --always-succeed
@@ -134,6 +138,7 @@ linux-rel-css:
   commands:
     - ./mach clean-nightlies --keep 3 --force
     - ./mach clean-cargo-cache --keep 3 --force
+    - ./mach clean
     - ./mach build --release --with-debug-assertions
     - ./mach test-wpt --release --processes 24 --total-chunks 2 --this-chunk 2 --log-raw test-wpt.log --log-errorsummary wpt-errorsummary.log --always-succeed
     - ./mach filter-intermittents wpt-errorsummary.log --log-intermittents intermittents.log --log-filteredsummary filtered-wpt-errorsummary.log --tracker-api default --reporter-api default
@@ -145,6 +150,7 @@ linux-rel-css:
 linux-nightly:
   - ./mach clean-nightlies --keep 3 --force
   - ./mach clean-cargo-cache --keep 3 --force
+  - ./mach clean
   - ./mach build --release
   - ./mach package --release
   - ./mach upload-nightly linux