Use filename instead of index in test

[Eric]

Summary

In some environments this test could fail if start.S has its own DWARF CompileUnit or similar are included before the DWARF CompileUnit for the file.
This change makes the test independent of the index of the compile unit, instead checking the filename.

[herhut]

Thanks!

[jankratochvil]

s/if symbols for start.S or similar are included before the symbols for the file./if start.S has its own DWARF CompileUnit or similar are included before the DWARF CompileUnit for the file./

You could IMO check it in as an obvious fix, thanks.

[Eric]

Thanks for the quick review! Please commit it as I do not have permission to do that.

lldb/test/Shell/SymbolFile/DWARF/dwarf5-lazy-dwo.c

 // CHECK: 1.dwo,
 // CHECK-NOT: 2.dwo,
 // CHECK: (lldb) run
 // CHECK-NOT: 2.dwo,
 // CHECK: stop reason = breakpoint
 // CHECK-NOT: 2.dwo,
 // CHECK: (lldb) image lookup
 // CHECK-NOT: 2.dwo,
-// CHECK: CompileUnit: id = {0x00000000}, file =
-// CHECK-SAME: language = "c99"
+// CHECK: CompileUnit: id =
+// CHECK-SAME: /dwarf5-lazy-dwo.c", language = "c99"
 // CHECK-NOT: 2.dwo,
 
 #ifdef ONE
 int main() { return 0; }
 #else
 int x;
 #endif