AAPT: Don't keep processing files that failed to be added

AAPT will continue ahead without reporting an error if a file
failed to be added to the ResourceTable. This would cause crashes
later when the file was assumed to be present.

Bug:30200166
Change-Id: Ieb2daf97ccf0345153b6f4598d130a38d108c937
diff --git a/tools/aapt/ResourceTable.cpp b/tools/aapt/ResourceTable.cpp
index 6a4b637..6d80a69 100644
--- a/tools/aapt/ResourceTable.cpp
+++ b/tools/aapt/ResourceTable.cpp
@@ -4521,6 +4521,7 @@
         const ConfigDescription& sourceConfig,
         const int sdkVersionToGenerate) {
     assert(sdkVersionToGenerate > sourceConfig.sdkVersion);
+    assert(configList != NULL);
     const DefaultKeyedVector<ConfigDescription, sp<ResourceTable::Entry>>& entries
             = configList->getEntries();
     ssize_t idx = entries.indexOfKey(sourceConfig);