Cirrus-CI: switch to -lite LLVM package for native run

This reduces CI cycle time (a small amount).

Suggested by:	brooks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D40136

.cirrus.yml

@@ -19,27 +19,31 @@ task:
     env:
       TARGET: amd64
       TARGET_ARCH: amd64
-      TOOLCHAIN_PKG: llvm15
+      TOOLCHAIN: llvm15
+      TOOLCHAIN_PKG: ${TOOLCHAIN}-lite
   - name: World and kernel arm64 build and boot smoke test
     only_if: $CIRRUS_REPO_FULL_NAME != 'freebsd/freebsd-src'
     trigger_type: manual
     env:
       TARGET: arm64
       TARGET_ARCH: aarch64
-      TOOLCHAIN_PKG: llvm15
+      TOOLCHAIN: llvm15
+      TOOLCHAIN_PKG: ${TOOLCHAIN}
   - name: World and kernel gcc12 amd64 build and boot smoke test (manual)
     only_if: $CIRRUS_REPO_FULL_NAME != 'freebsd/freebsd-src'
     trigger_type: manual
     env:
       TARGET: amd64
       TARGET_ARCH: amd64
-      TOOLCHAIN_PKG: amd64-gcc12
+      TOOLCHAIN: amd64-gcc12
+      TOOLCHAIN_PKG: ${TOOLCHAIN}
   - name: World and kernel gcc12 amd64 build and boot smoke test (FreeBSD repo)
     only_if: $CIRRUS_REPO_FULL_NAME == 'freebsd/freebsd-src'
     env:
       TARGET: amd64
       TARGET_ARCH: amd64
-      TOOLCHAIN_PKG: amd64-gcc12
+      TOOLCHAIN: amd64-gcc12
+      TOOLCHAIN_PKG: ${TOOLCHAIN}
   timeout_in: 120m
   install_script:
   - sh .cirrus-ci/pkg-install.sh ${TOOLCHAIN_PKG} git-lite
@@ -54,10 +58,10 @@ task:
   - chown user:user /usr/obj/$(pwd -P)
 
   script:
-  - su user -c "make -j$(sysctl -n hw.ncpu) CROSS_TOOLCHAIN=${TOOLCHAIN_PKG} WITHOUT_TOOLCHAIN=yes buildworld buildkernel"
+  - su user -c "make -j$(sysctl -n hw.ncpu) CROSS_TOOLCHAIN=${TOOLCHAIN} WITHOUT_TOOLCHAIN=yes buildworld buildkernel"
 
   package_script:
-  - su user -c "make CROSS_TOOLCHAIN=${TOOLCHAIN_PKG} WITHOUT_TOOLCHAIN=yes packages"
+  - su user -c "make CROSS_TOOLCHAIN=${TOOLCHAIN} WITHOUT_TOOLCHAIN=yes packages"
 
   package_check_script:
   - su user -c "/usr/libexec/flua tools/pkgbase/metalog_reader.lua -c /usr/obj/$(pwd -P)/${TARGET}.${TARGET_ARCH}/worldstage/METALOG"