cmd/compile: remove FmtFlag save and restore
cmd/compile: remove FmtFlag save and restore

It is unnecessary.

Passes toolstash -cmp.

Change-Id: I7c03523b6110c3d9bd5ba2b37d9a1e17a7ae570e
Reviewed-on: https://go-review.googlesource.com/38145
Run-TryBot: Josh Bleecher Snyder <cdc248cc4d32e4fbfe04e45228163bcecd48a0b9@gmail.com>
Reviewed-by: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>

golang/go,derekmarcotte/go,CAFxX/go,linux-on-ibm-z/go,derekmarcotte/go,Cofyc/go,codestation/go,CAFxX/go,akutz/go,nawawi/go,cloudflare/go,golang/go,polyverse-security/go,ImJasonH/go,nawawi/go,josharian/go,ImJasonH/go,josharian/go,CAFxX/go,CAFxX/go,codestation/go,CAFxX/go,vsekhar/elastic-go,christopher-henderson/Go,golang/go,derekmarcotte/go,josharian/go,nawawi/go,vsekhar/elastic-go,akutz/go,ImJasonH/go,derekmarcotte/go,linux-on-ibm-z/go,josharian/go,Cofyc/go,codestation/go,akutz/go,vsekhar/elastic-go,vsekhar/elastic-go,josharian/go,cloudflare/go,cloudflare/go,codestation/go,polyverse-security/go,linux-on-ibm-z/go,vsekhar/elastic-go,cloudflare/go,linux-on-ibm-z/go,golang/go,CAFxX/go,linux-on-ibm-z/go,vsekhar/elastic-go,derekmarcotte/go,codestation/go,ImJasonH/go,vsekhar/elastic-go,derekmarcotte/go,linux-on-ibm-z/go,golang/go,vsekhar/elastic-go,nawawi/go,polyverse-security/go,akutz/go,nawawi/go,ImJasonH/go,akutz/go,linux-on-ibm-z/go,derekmarcotte/go,nawawi/go,josharian/go,linux-on-ibm-z/go,polyverse-security/go,codestation/go,josharian/go,codestation/go,josharian/go,polyverse-security/go,CAFxX/go,nawawi/go,codestation/go,CAFxX/go,Cofyc/go,ImJasonH/go,derekmarcotte/go,cloudflare/go,cloudflare/go,polyverse-security/go,nawawi/go,Cofyc/go,Cofyc/go,Cofyc/go,ImJasonH/go,Cofyc/go,polyverse-security/go,akutz/go,golang/go,cloudflare/go,cloudflare/go,akutz/go,akutz/go,golang/go,golang/go,Cofyc/go,ImJasonH/go,polyverse-security/go