dumpstate: Emit MGLRU configuration

Bugreports should contain MGLRU state. MGLRU is default enabled, but can
be modified by system property or by vendor init.rc. Directly read the
MGLRU state from the kernel into bugreports.

Bug: 412360488
Test: adb bugreport br.zip
Flag: NONE Fails gracefully even if file doesn't exist / can't be accessed
Change-Id: I2104a5795329298eafcdddd06b65a809dc7a9994