Brian Gianforcaro 2038d2c49e LibELF: Apply some minor optimizations to symbol lookup ...

Optimizations:

- Make sure `DT_SYMTAB` is a string view literal, instead of string.

- DynamicObject::HashSection::lookup_sysv_symbol should be using
  raw_name() from symbol comparison to avoid needlessly calling
  `strlen`, when the StrinView::operator= walks the cstring without
  calling `strlen` first.

- DynamicObject::HashSection::lookup_gnu_symbol shouldn't create a
  symbol unless we know the hashes match first.

In order to test these changes I enabled Undefined behavior sanitizer
which creates a huge amount of relocations, and then ran the browser
with the help argument 100 times. The browser is a fairly big app with
a few different libraries being loaded, so it seemed liked a good
target.

Command: `time -n 100 br --help`

Before:
```
Timing report:
==============
Command:         br --help
Average time:    3897.679931 ms
Excluding first: 3901.242431 ms
```

After:
```
Timing report:
==============
Command:         br --help
Average time:    3612.860107 ms
Excluding first: 3613.54541 ms
```

2021-08-28 20:03:08 +02:00

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