Revert "Clean up stale code in BigtableService"

[tvalentyn]

Reverts #30172

[tvalentyn]

precommits still fail, so reverting the PR is not warranted. https://github.com/apache/beam/runs/25516604753

cc: @shunping

java.io.IOException: Error matching file spec gs://apache-beam-samples/shakespeare/sonnets.txt: status ERROR
	at org.apache.beam.sdk.io.FileSystems.matchSingleFileSpec(FileSystems.java:196)
	at org.apache.beam.sdk.util.ExplicitShardedFile.<init>(ExplicitShardedFile.java:58)
	at org.apache.beam.examples.WindowedWordCountIT.testWindowedWordCountPipeline(WindowedWordCountIT.java:174)
	at org.apache.beam.examples.WindowedWordCountIT.testWindowedWordCountInStreamingStaticSharding(WindowedWordCountIT.java:113)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)