Unconditionally install shim apex on system partition

Trying to do it on per-device basis is prone to errors and already
bitten us several times. For example, currently aosp_taimen doesn't
install shim apex on system partition, but specifies
ro.apex.updatable = "true", which means that it doesn't pass CTS tests.

Unconditionally installing shim APEX shouldn't introduce any problems
since apexd will skip its activation of devices that don't support
updatable APEX.

Test: m checkbuild
Bug: 140957666
Change-Id: I6b5e668b40b97752295c831684a7291842533c40
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index ec373db..4d7904d 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -49,6 +49,7 @@
     cgroups.json \
     charger \
     cmd \
+    com.android.apex.cts.shim.v1_prebuilt \
     com.android.conscrypt \
     com.android.i18n \
     com.android.location.provider \
diff --git a/target/product/mainline_system.mk b/target/product/mainline_system.mk
index 721f5d9..b8f2838 100644
--- a/target/product/mainline_system.mk
+++ b/target/product/mainline_system.mk
@@ -105,9 +105,6 @@
 # Enable dynamic partition size
 PRODUCT_USE_DYNAMIC_PARTITION_SIZE := true
 
-PRODUCT_PACKAGES += \
-    com.android.apex.cts.shim.v1_prebuilt
-
 PRODUCT_ENFORCE_RRO_TARGETS := *
 
 PRODUCT_NAME := mainline_system