e2bc9fe9d5ac82457bc6050bf705ff43a1b05cbf in platform/art project added
the dynamic linker to the runtime APEX. Since the dynamic linker has
been labeled as 'system_linker_exec' so does the linker in the APEX.

Bug: 120266448
Test: ls -Z /apex/com.android.runtime/bin/linker
u:object_r:system_linker_exec:s0 /apex/com.android.runtime/bin/linker

Change-Id: I243b86a74d94058b3283830c32232c6584639ff3

Code in bionic / libcore will now look in the runtime
APEX module for data files.

Bug: 119293618
Bug: 119390260
Test: build / treehugger only
Change-Id: I965c763e7f0452b8ef5ffbf730733e9a41254beb

There is no real need to access the manifest.json (which is being
renamed in other CLs anyway). So remove the access to it.

Bug: 119672727
Test: m, installed on device, boots.
Change-Id: I2d82062031da36f871b2a64d97a50a6f1e6fc3dd

Also rename `file_contexts` for the "Debug" Runtime APEX module
(containing both release and debug variants, as well as additional
tools).

Test: make com.android.runtime
Test: make com.android.runtime.release
Test: make com.android.runtime.debug
Test: art/build/apex/runtests.sh
Bug: 113373927
Change-Id: I6b917d7f5b1734aeb717932081c7b03366ef2774

It was <name>_file_context before. Changing for better readability.

Bug: 119034475
Test: m apex.test com.android.tzdata com.android.runtime
Change-Id: Ic9d6479dfed56ac474c574343a38b5f73dde3c05

For centralized development of sepolices, file_contexts files for APEXes
are all moved to under /system/seplicy.

Bug: 119034475
Bug: 113373927
Test: m apex.test com.android.tzdata com.android.runtime com.android.media
Change-Id: I9bf4874793db4dbdb75cbd759ae95f72d7281007