Fix SeekableAutoCloseInputStream#read with len=0

When the read length is zero, javadoc specifies it returns 0.
This fixes the behavior.

Bug: 336939044
Bug: 337138079
Test: CtsResourcesTestCases:AssetFileDescriptor_AutoCloseInputStreamTest
Change-Id: I4714f831f2c347cd83d8e93bdec97eb6c2598f75
1 file changed