Fix one more exception handling issue

Fix one more exception handling issue

This change fixes exception handling issue that resulted in a finally block being invoked multiple
times in case of a rethrown exception in some specific cases.
The problem was caused by the ExceptionTracker::StackRange::CombineWith that was not handling
correctly the case when the current stack range was empty. It was copying only the upper limit
from the previous range and leaving the lower limit at the default (max) value.
This case happens in the interleaved exception handling when processing the first managed
frame after a block of native frames was unwound.
There is one additional fix in the UnwindManagedExceptionPass1 where we were popping one
frame from the thread's frame list before performing the native frames unwind. This was
not correct since in some cases, there can be more frames that need to be removed.