Support unwinding though the switch interpreter.

Wrap the switch interpreter in small assembly method which defines
DEX PC in CFI and thus it allows libunwind to backtrace through it.

Bug: 22414682
Test: testrunner.py --host -t 137
Test: testrunner.py --target -t 137

(cherry picked from commit 946bb09a5adc7d591498b4504aa5d9354457953e)
Merged-In: I31dad9f0fb446151baaa99234b64f25c8ca2fa87
Change-Id: I4b5239af24480f7314336b4610c3c50641ed50ed
22 files changed