Remove TxtStubLibraries.bp

The modules defined in TxtStubLibraries.bp are currently not in the
critical path of the from-text stub build, because the from-text vs
from-source switching is encapsulated within the stub library modules.
Therefore, remove the modules altogether.

Test: m nothing --build-from-text-stub
Bug: 287522618
Change-Id: I249edcdf596c8a82058e1bfb17da863c2b5dd7a7

java/core-libraries/Android.bp

@@ -524,7 +524,3 @@ java_system_modules {
         "art-module-intra-core-api-stubs-system-modules-lib",
     ],
 }
-
-build = [
-    "TxtStubLibraries.bp",
-]