Use findstring to check MODULE_BUILD_FROM_SOURCE

Android 12 can have _compressed target
(e.g com.google.android.conscrypt_compressed),
changed function from `filter` to `findstring`

Same change applied to com.google.android.art check

Also modify to check `true` value of the MODULE_BUILD_FROM_SOURCE
to filter out both unset variable and `false`

Test: adding one error code temporally, install prebuilt
  train, and check result with,without this fix

    MODULE_BUILD_FROM_SOURCE := true
  + $(error we are here, true $(PRODUCT_PACKAGES))
  endif

Bug: 197282276
Change-Id: I864ba1bb5da61ccc6b8576029ab6c569959b2c93
(cherry picked from commit 32c048c3796f259512e97fe054410787f18f9fb6)
diff --git a/core/android_soong_config_vars.mk b/core/android_soong_config_vars.mk
index 9d7c1bf..5e63a25 100644
--- a/core/android_soong_config_vars.mk
+++ b/core/android_soong_config_vars.mk
@@ -29,7 +29,7 @@
 $(call add_soong_config_var,ANDROID,TARGET_ENABLE_MEDIADRM_64)
 $(call add_soong_config_var,ANDROID,BOARD_USES_ODMIMAGE)
 
-ifeq (,$(filter com.google.android.conscrypt,$(PRODUCT_PACKAGES)))
+ifeq (,$(findstring com.google.android.conscrypt,$(PRODUCT_PACKAGES)))
   # Prebuilt module SDKs require prebuilt modules to work, and currently
   # prebuilt modules are only provided for com.google.android.xxx. If we can't
   # find one of them in PRODUCT_PACKAGES then assume com.android.xxx are in use,
@@ -49,7 +49,7 @@
   # Always build from source for the module targets. This ought to be covered by
   # the TARGET_BUILD_APPS check above, but there are test builds that don't set it.
   SOONG_CONFIG_art_module_source_build := true
-else ifdef MODULE_BUILD_FROM_SOURCE
+else ifeq (true,$(MODULE_BUILD_FROM_SOURCE))
   # Build from source if other Mainline modules are.
   SOONG_CONFIG_art_module_source_build := true
 else ifneq (,$(filter true,$(NATIVE_COVERAGE) $(CLANG_COVERAGE)))
@@ -72,7 +72,7 @@
 else ifneq (,$(filter dex2oatds dex2oats,$(PRODUCT_HOST_PACKAGES)))
   # Some products depend on host tools that aren't available as prebuilts.
   SOONG_CONFIG_art_module_source_build := true
-else ifeq (,$(filter com.google.android.art,$(PRODUCT_PACKAGES)))
+else ifeq (,$(findstring com.google.android.art,$(PRODUCT_PACKAGES)))
   # TODO(b/192006406): There is currently no good way to control which prebuilt
   # APEX (com.google.android.art or com.android.art) gets picked for deapexing
   # to provide dex jars for hiddenapi and dexpreopting. Instead the AOSP APEX is
@@ -90,6 +90,6 @@
 $(call add_soong_config_var_value,ANDROID,library_linking_strategy,prefer_static)
 endif
 
-ifdef MODULE_BUILD_FROM_SOURCE
+ifeq (true,$(MODULE_BUILD_FROM_SOURCE))
 $(call add_soong_config_var_value,ANDROID,module_build_from_source,true)
 endif