Rework common_periodicChecks.
The function was rewritten to optimize the common path. The control flow
now matches the C version, which tests for debugger/profiler even if the
previous test for suspension came up true.
This also adds a minor optimization on the test for debugger attachment,
allowing us to skip a load from memory if the process is simply not
debuggable. (The optimization isn't yet enabled because a similar change
must be made to the x86 asm code.)
The VM apparently hadn't been built without debugging/profiling support
for a while, so this fixes those places (necessary to be able to test
all forms of the new code).
Bug 2634642.
Change-Id: I096b58c961bb73ee0d128ba776d68dbf29bba924