[PATCH] gas: copy st_size only if unset

[Alan Modra]

Your patch regressed these tests.  Please investigate.

aarch64_be-linux-gnu_ilp32  +FAIL: ELF symbol size
aarch64-elf  +FAIL: ELF symbol size
aarch64-linux  +FAIL: ELF symbol size
alpha-linux  +FAIL: ELF symbol size
alpha-netbsd  +FAIL: ELF symbol size
alpha-unknown-freebsd4.7  +FAIL: ELF symbol size
hppa64-hp-hpux11.23  +FAIL: ELF symbol size
hppa64-linux  +XPASS: .reloc against undefined local symbol (PR 27228)
hppa-linux  +XPASS: .reloc against undefined local symbol (PR 27228)
nds32be-elf  +FAIL: readelf -wiaoRlL dw5
nds32le-linux  +FAIL: readelf -wiaoRlL dw5
riscv32-elf  +FAIL: ELF symbol size
riscv64-linux  +FAIL: ELF symbol size

-- 
Alan Modra
Australia Development Lab, IBM