runtime, syscall: link Solaris binaries directly instead of using dlopen/dlsym

Before CL 8214 (use .plt instead of .got on Solaris) Solaris used a
dynamic linking scheme that didn't permit lazy binding. To speed program
startup, Go binaries only used it for a small number of symbols required
by the runtime. Other symbols were resolved on demand on first use, and
were cached for subsequent use. This required some moderately complex
code in the syscall package.

CL 8214 changed the way dynamic linking is implemented, and now lazy
binding is supported. As now all symbols are resolved lazily by the
dynamic loader, there is no need for the complex code in the syscall
package that did the same. This CL makes Go programs link directly
with the necessary shared libraries and deletes the lazy-loading code
implemented in Go.

Change-Id: Ifd7275db72de61b70647242e7056dd303b1aee9e
Reviewed-on: https://go-review.googlesource.com/9184


Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>