Fix a bug for create_gcov after changing offset in symbol_map from uint32_t to uint64_t.
Fix a bug for create_gcov after changing offset in symbol_map from uint32_t to uint64_t.

After changing offset in symbol_map from uint32_t to uint64_t, the
encoding and decoding of offset from line and discriminator should be
changed accordingly. This is correct for the part guarded with HAVE_LLVM
but incorrect for the rest. This patch fixes the encoding error.

google/autofdo,google/autofdo,google/autofdo