java/lint: enable lint on non-generated srcjar

Soong made the assumption that any .srcjar was generated source, for
which the lints were not executed. It may not be the case for .srcjar
that are manually created. Run the linter on any .srcjar that has been
provided within the src attribute, but ignore any source generated
.srcjar (such as .proto or .aidl).

Test: m lint-check
Bug: 228774926
Change-Id: If214fb57f54049fce54297ee6bf65d734b3d2e6d