Test the exact archive format. In particular, test which file names use the
string table or not.

RUN: mkdir -p %t
RUN: cd %t

RUN: echo -n bar. > 0123456789abcde
RUN: echo -n zed. > 0123456789abcdef

RUN: rm -f test.a
RUN: llvm-ar rc test.a 0123456789abcde 0123456789abcdef
RUN: cat test.a | FileCheck -strict-whitespace %s

CHECK:      !<arch>
CHECK-NEXT: //                                              18        `
CHECK-NEXT: 0123456789abcdef/
CHECK-NEXT: 0123456789abcde/{{................................}}4         `
CHECK-NEXT: bar./0              {{................................}}4         `
CHECK-NEXT: zed.