Remove frame_id from InstrumentationStackFrame

Computing the frame id when pushing the instrumentation stack is
expensive and causes slowdown when debugger is attached.
The only use of the frame_id is to properly order the method enter
events when instrumenting the stack. It is easier to just record the
methods on the stack in order while walking instead of using frame_id.

Bug: 206029744
Test: art/test.py
Change-Id: Ia69a8f2a60c2c20eab8ac49e337da0bb272fe92e