ANDROID: Adding Image.gz and boot-gz.img

This adds <10 seconds for a LTO=thin build, while the original
build time is about ~250 seconds on a build machine with 48 2.60 GHz
processors and 64GB RAM.

Within the 10 seconds, ~3 seconds spent on building Image.gz,
~5 seconds for packing Image.gz as boot-gz.img and <1 second for
including the boot-gz.img into the boot-img.tar.gz.

Bug: 233352819
Test: LTO=thin BUILD_CONFIG=common/build.config.gki.aarch64 build/build.sh
Signed-off-by: Bowgo Tsai <bowgotsai@google.com>
Change-Id: I283ef004d1233d2e175573b893379e0d68221353
(cherry picked from commit 2ad997b4d1d4343d7d79e900c6f60b0272f65a47)

build.config.gki.aarch64

@@ -4,6 +4,7 @@
 
 MAKE_GOALS="${MAKE_GOALS}
 Image.lz4
+Image.gz
 "
 
 ABI_DEFINITION=android/abi_gki_aarch64.xml
@@ -28,6 +29,7 @@ android/abi_gki_aarch64_oplus
 
 FILES="${FILES}
 arch/arm64/boot/Image.lz4
+arch/arm64/boot/Image.gz
 "
 
 # Update BUILD.bazel, define_common_kernels() if the value is not 1.
@@ -43,4 +45,5 @@ BUILD_GKI_CERTIFICATION_TOOLS=1
 
 BUILD_GKI_ARTIFACTS=1
 BUILD_GKI_BOOT_IMG_SIZE=67108864
+BUILD_GKI_BOOT_IMG_GZ_SIZE=47185920
 BUILD_GKI_BOOT_IMG_LZ4_SIZE=53477376