Use dwarf 5 for Linux binaries (BinSkim)

[dagood]

• Related upstream issue: cmd/compile: consider using DWARF 5 golang/go#26379

Example BinSkim issue: https://devdiv.visualstudio.com/DevDiv/_queries/edit/1727456

https://github.com/microsoft/binskim/blob/main/docs/BinSkimRules.md#rule-BA3004GenerateRequiredSymbolFormat

'goboringcrypto_linux_amd64.syso' is using debugging dwarf version '4'. The dwarf version 5 contains more information and should be used. To enable the debugging version 5 use '-gdwarf-5'.

Strangely, BinSkim only detects dwarf 4 in src\crypto\internal\boring\goboringcrypto_linux_amd64.syso, not the binaries we actually build. But our binaries do use version 4:

$ llvm-dwarfdump -r 1 go/bin/go | head | grep Compile
0x00000000: Compile Unit: length = 0x00000b85, format = DWARF32, version = 0x0004, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x00000b89)