Disable hidden API checks for WellKnownClasses

WellKnownClasses acquires handles to some special-cased classes/methods/
fields at startup using JNI. If the process has hidden API checks
enabled, it will prevent WellKnownClasses from doing that as the request
is coming from an unattached native thread. This patch disables the
checks for the duration of the initializer.

Test: check there are no log message during compilation on target
Bug: 64382372
Change-Id: I31b2293336ac634ce0e07fa4edc754cd7d1568e2