The new behavior matches GNU objdump. A pair of angle brackets makes tests slightly easier.
`.foo:` is not unique and thus cannot be used in a `CHECK-LABEL:` directive.
Without `-LABEL`, the CHECK line can match the `Disassembly of section`
line and causes the next `CHECK-NEXT:` to fail.
```
Disassembly of section .foo:
0000000000001634 .foo:
```
Bdragon: <> has metalinguistic connotation. it just "feels right"
Reviewed By: rupprecht
Differential Revision: https://reviews.llvm.org/D75713
Disassembly of instructions can fail when llvm-objdump is not given the right set of
architecture features, for example when the source is compiled with:
clang -march=..+ext1+ext2
and disassembly is attempted with:
llvm-objdump -mattr=+ext1
This patch avoids further analysing unknown instructions (as was happening
before) when disassembly has failed.
Differential Revision: https://reviews.llvm.org/D73531
Fangrui Song