runtime, syscall: remove unused bits from Solaris implementation

CL 9184 changed the runtime and syscall packages to link Solaris binaries
directly instead of using dlopen/dlsym but did not remove the unused (and
now broken) references to dlopen, dlclose, and dlsym.

Fixes #11923

Change-Id: I36345ce5e7b371bd601b7d48af000f4ccacd62c0
Reviewed-on: https://go-review.googlesource.com/13410Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>

src/runtime/syscall2_solaris.go

@@ -9,9 +9,6 @@ import _ "unsafe" // for go:linkname
 //go:cgo_import_dynamic libc_chdir chdir "libc.so"
 //go:cgo_import_dynamic libc_chroot chroot "libc.so"
 //go:cgo_import_dynamic libc_close close "libc.so"
-//go:cgo_import_dynamic libc_dlclose dlclose "libc.so"
-//go:cgo_import_dynamic libc_dlopen dlopen "libc.so"
-//go:cgo_import_dynamic libc_dlsym dlsym "libc.so"
 //go:cgo_import_dynamic libc_execve execve "libc.so"
 //go:cgo_import_dynamic libc_fcntl fcntl "libc.so"
 //go:cgo_import_dynamic libc_gethostname gethostname "libc.so"
@@ -30,9 +27,6 @@ import _ "unsafe" // for go:linkname
 //go:linkname libc_chdir libc_chdir
 //go:linkname libc_chroot libc_chroot
 //go:linkname libc_close libc_close
-//go:linkname libc_dlclose libc_dlclose
-//go:linkname libc_dlopen libc_dlopen
-//go:linkname libc_dlsym libc_dlsym
 //go:linkname libc_execve libc_execve
 //go:linkname libc_fcntl libc_fcntl
 //go:linkname libc_gethostname libc_gethostname

src/syscall/asm_solaris_amd64.s

@@ -23,15 +23,6 @@ TEXT ·chroot1(SB),NOSPLIT,$0
 TEXT ·close(SB),NOSPLIT,$0
 	JMP	runtime·syscall_close(SB)
 
-TEXT ·dlopen(SB),NOSPLIT,$0
-	JMP	runtime·syscall_dlopen(SB)
-
-TEXT ·dlclose(SB),NOSPLIT,$0
-	JMP	runtime·syscall_dlclose(SB)
-
-TEXT ·dlsym(SB),NOSPLIT,$0
-	JMP	runtime·syscall_dlsym(SB)
-
 TEXT ·execve(SB),NOSPLIT,$0
 	JMP	runtime·syscall_execve(SB)