[lldb] Refactor InstrumentationRuntimeAsan and add a new plugin
InstrumentationRuntimeLibsanitizers.
This commit refactors InstrumentationRuntimeASan by pulling out reusable
code into a separate ReportRetriever class. The purpose of the
refactoring is to allow reuse of the ReportRetriever class in another
plugin.
The commit also adds InstrumentationRuntimeASanLibsanitizers, a new runtime
plugin for ASan. The plugin provides the same
functionality as InstrumentationRuntimeASan, but provides a different
set of symbols/library names to search for while activating the plugin.
rdar://112491689