Remove installFiles from ModuleBase.

This is to limit the direct accesses to the internal fields of a
module in order to better support incremental caching. To access
the install files data from singleton context or other modules'
context use providers thru the provided wrapper; to access it
from the same module inside GenerateBuildActions use ctx which is
short-lived only inside this method.

Bug: 358425833
Test: CI
Change-Id: I337b07a2ef95fb2a898ac2f9277160a3f76a603c
diff --git a/android/androidmk.go b/android/androidmk.go
index e9df752..12eb6e5 100644
--- a/android/androidmk.go
+++ b/android/androidmk.go
@@ -861,6 +861,7 @@
 	}
 
 	data := provider.AndroidMk()
+
 	if data.Include == "" {
 		data.Include = "$(BUILD_PREBUILT)"
 	}