[JITLink][MachO][AArch64] Specify endianness, fix name of testcase.

The "MachO_ptrauth_noolloc_sections.yaml" testcase had a typo in the name, and
didn't explicitly specify its endianness. This was causing it to fail when
enabled on big endian platforms.

See conversation in llvm#167902

Author: lhames

llvm/test/ExecutionEngine/JITLink/AArch64/MachO_ptrauth_noolloc_sections.yaml renamed to llvm/test/ExecutionEngine/JITLink/AArch64/MachO_ptrauth_noalloc_sections.yaml

@@ -16,6 +16,7 @@
 # CHECK: llvm-jitlink error: {{.*}} unsupported edge kind Pointer64Authenticated
 
 --- !mach-o
+IsLittleEndian: true
 FileHeader:
   magic:           0xFEEDFACF
   cputype:         0x100000C