[LLDB] Test SVE dynamic resize with multiple threads

This patch adds a new test case which depends on AArch64 SVE support and
dynamic resize capability enabled. It created two seperate threads which
have different values of sve registers and SVE vector granule at various
points during execution.

We test that LLDB is doing the size and offset updates properly for all
of the threads including the main thread and when we VG is updated using
prctl call or by 'register write vg' command the appropriate changes are
also update in register infos.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D82866