CI: Use mold as linker on Linux

Author: Repiteo

.github/workflows/linux_builds.yml

@@ -35,11 +35,11 @@ jobs:
             # Validate godot-cpp compatibility on one arbitrary editor build.
             godot-cpp: true
 
-          - name: Editor with doubles and GCC sanitizers (target=editor, tests=yes, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=gold)
+          - name: Editor with doubles and GCC sanitizers (target=editor, tests=yes, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=mold)
             cache-name: linux-editor-double-sanitizers
             target: editor
             # Debug symbols disabled as they're huge on this build and we hit the 14 GB limit for runners.
-            sconsflags: dev_build=yes scu_build=yes debug_symbols=no precision=double use_asan=yes use_ubsan=yes linker=gold
+            sconsflags: dev_build=yes scu_build=yes debug_symbols=no precision=double use_asan=yes use_ubsan=yes linker=mold
             bin: ./bin/godot.linuxbsd.editor.dev.double.x86_64.san
             build-mono: false
             tests: true
@@ -162,6 +162,10 @@ jobs:
       - name: Extract pre-built AccessKit
         run: unzip -o accesskit-c-0.15.1/accesskit_c.zip
 
+      - name: Install mold linker
+        if: matrix.proj-test
+        uses: rui314/setup-mold@v1
+
       - name: Compilation
         uses: ./.github/actions/godot-build
         with: