[lldb] Removed scoped timer from ReadMemoryFromFileCache

`ReadMemoryFromFileCache` can be called at a high rate, and has fast execution.
Signposts for high rate & brief duration can have a negative impact on tracing;
emitting a high volume signposts can lead to blocking, affecting performance,
and total volume makes human review of the trace harder because of the noise.

Differential Revision: https://reviews.llvm.org/D121226

lldb/source/Target/Target.cpp

@@ -1684,7 +1684,6 @@ bool Target::ModuleIsExcludedForUnconstrainedSearches(
 
 size_t Target::ReadMemoryFromFileCache(const Address &addr, void *dst,
                                        size_t dst_len, Status &error) {
-  LLDB_SCOPED_TIMER();
   SectionSP section_sp(addr.GetSection());
   if (section_sp) {
     // If the contents of this section are encrypted, the on-disk file is