Don't minimize debug information if module explicitly asks for it

In some configurations (for ex: go, auto) we minimize debug information
to reduce disk and memory usage. However some tests need the debug
information to work as expected. If a test explicitly requests for debug
information by passing "-g" to javac flags don't add "-g:source,lines"
to minimize debug information. Javac gives priority to -g:source,lines
and doesn't respect the order. So check if there is a -g flag before
adding flags to minimize debug information.

Test: atest CtsJvmtiRunTest1912HostTestCases android.jvmti.cts.JvmtiHostTest1912#testJvmti
Change-Id: I45e0f5fa9e79c16c2ff6e9413941a9a637753653