Temporarily add method to get java binary tool

cc binaries are moving from out/soong/host/linux-x86/bin to
out/host/linux-86/bin first, to be followed by java binaries.
Temporarily add a method that gets the java binary path while
it is different from the cc binary path.

Bug: 204136549
Test: m checkbuild
Change-Id: I04a7e741436da6be68078f23d074870413a5bb5e