[lldb/test] simplify basic-elf.yaml

Explicit dynsym/dynstr sections were added in a6370d5 to compensate for
a yaml2obj change D74764. This test doesn't need those sections, so
instead I just delete the explicit section blocks, and also the
"DynamicSymbols" block, which triggers their implicit generation.

lldb/test/Shell/SymbolFile/Breakpad/Inputs/basic-elf.yaml

@@ -20,16 +20,6 @@ Sections:
     Address:         0x00000000004000B0
     AddressAlign:    0x0000000000000010
     Size:            0x42
-  - Name:            .dynsym
-    Type:            SHT_PROGBITS
-    Flags:           [ SHF_ALLOC ]
-    Address:         0x0
-  - Name:            .dynstr
-    Type:            SHT_STRTAB
-    Flags:           [ SHF_ALLOC ]
-    Address:         0x0
-Symbols:         
-DynamicSymbols:  
 ProgramHeaders:
   - Type: PT_LOAD
     Flags: [ PF_X, PF_R ]