[llvm-objcopy] Fix strip-all-gnu test

[asi-sc]

Summary

Originally the test has a bug: in the input YAML .symtab.dyn section has a type
repeated twice with different values (SHT_SYMTAB and SHT_NOBITS). YAML parser
took SHT_NOBITS as a type of the section, so the test wasn't checking the desired
case.

This patch changes the test to verify that a section with SHT_SYMTAB type and
SHF_ALLOC flag is not removed when --strip-all-gnu flag present.

[asi-sc]

Discussion related to this fix can be found in D141848 (see 1 , 2, 3).

[jhenderson]

LGTM, thanks. Maybe give 24 hours in case anybody else has any comments.

llvm/test/tools/llvm-objcopy/ELF/strip-all-gnu.test

 # RUN: yaml2obj %s -o %t
-# RUN: llvm-objcopy --strip-all-gnu %t %t2
-# RUN: llvm-strip --strip-all-gnu %t -o %t3
+# RUN: llvm-objcopy --strip-all-gnu --allow-broken-links %t %t2
+# RUN: llvm-strip --strip-all-gnu --allow-broken-links %t -o %t3
 # RUN: llvm-readobj --file-headers --sections %t2 | FileCheck %s
 # RUN: cmp %t2 %t3
 
 # Show that the debug section in a segment was removed, to match GNU.
 # First validate that the offset in use is correct.
 # RUN: llvm-objcopy %t %t4
 # RUN: od -t x1 -N 4 -j 120 %t4 | FileCheck %s --ignore-case --check-prefix=COPY-BYTES
 # RUN: od -t x1 -N 4 -j 120 %t2 | FileCheck %s --ignore-case --check-prefix=STRIP-BYTES
 
 !ELF
 FileHeader:
   Class:           ELFCLASS64
   Data:            ELFDATA2LSB
   Type:            ET_REL
   Machine:         EM_X86_64
 Sections:
   - Name:            .debug_in_segment
     Type:            SHT_PROGBITS
     Flags:           [ ]
     Content:         "deadbeef"
   - Name:            .dynstr
     Type:            SHT_STRTAB
     Flags:           [ SHF_ALLOC ]
-  - Name:            .symtab.dyn
+  - Name:            .symtab
     Type:            SHT_SYMTAB
     Flags:           [ SHF_ALLOC ]
-    Type:            SHT_NOBITS
   - Name:            .text
     Type:            SHT_PROGBITS
     Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
     Size:            4
   - Name:            .debug_info
     Type:            SHT_PROGBITS
     Flags:           [ ]
     AddressAlign:    0x1
ProgramHeaders:
   # Use an arbitrary segment type to show that the segment type is unimportant.
   - Type:     0x61234567
     FirstSec: .debug_in_segment
     LastSec:  .debug_in_segment
 
 # CHECK: SectionHeaderCount: 8
 
 # CHECK:      Name: .dynstr
-# CHECK:      Name: .symtab.dyn
+# CHECK:      Name: .symtab
 # CHECK:      Name: .text
 # CHECK:      Name: .debug_loc
 # CHECK:      Name: .comment
 # CHECK:      Name: .random_section_name
 # CHECK:      Name: .shstrtab
 
 # COPY-BYTES:  de ad be ef
 # STRIP-BYTES: 00 00 00 00