Rename JavaLibraryNameFromText function

The "FromText" suffix is an implementation detail. Having this suffix in
the name can be also confusing because in certain settings (e.g. when
not run with --build-stub-from-text) it returns the name of the stub
module generated from source files

Test: go build ./java
Change-Id: I68678ddfaa3d68c8e1a945632e7512b5de33d9af