Rename target.linux[_x86[_64]] to target.linux_glibc[_x86[_64]]

In the future, target.linux will apply to all targets running a linux kernel
(android, linux_glibc, linux_bionic). So move all current users to the specific
linux_glibc.

There will be another cleanup pass later that will move some instances back to
target.linux if the properties should be shared with target.android and
target.linux_bionic, but target.linux needs to be removed first.

Test: out/soong/build.ninja identical before/after
Change-Id: Iea59380a4936c6d0555534d69b891b8ffdb9dfb6
Exempt-From-Owner-Approval: build system cleanup