[Profiler] Separate profiler instances for property inits and constructors (#25247)
Assign separate SILProfiler instances to stored property initializers
and constructors.
Starting with rdar://39460313, coverage reporting for these constructs
was bundled up into a single SILProfiler uniqued by the NominalTypeDecl.
There are two problems with doing this.
First, the shared SILProfiler is given a fake name that can't be
demangled. That breaks Xcode's reports. Second, the relationship
between SILProfiler and SILFunction is supposed to be 1:1. Having a
shared SILProfiler muddies things a bit and requires extra bookkeeping.
rdar://47467864