runtime: fix typo
runtime: fix typo

Change filepath reference from cmd/internal/ld/symtab.go to
cmd/link/internal/ld/symtab.go.

Change-Id: Icb207a2e2c82d3976787d2d5cfb0f8005696f738
GitHub-Last-Rev: 428d99c6ca97db79b7d8cdf24843df3492a9aeb0
GitHub-Pull-Request: golang/go#49518
Reviewed-on: https://go-review.googlesource.com/c/go/+/363276
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Trust: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

golang/go,CAFxX/go,cloudflare/go,CAFxX/go,golang/go,cloudflare/go,cloudflare/go,CAFxX/go,golang/go,nawawi/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,nawawi/go,cloudflare/go,nawawi/go,CAFxX/go,cloudflare/go,golang/go,golang/go,golang/go,nawawi/go,cloudflare/go,golang/go,cloudflare/go