[libfuzzer][Windows]Remove redundant check for use_libfuzzer

Remove redundant check for "use_libfuzzer" introduced in 6376140d.
This check is redundant and causes build failures because it stops
/OPT:NOLLDTAILMERGE from being used.

Bug: 884545
Change-Id: Ifb665751ff568ff557c4a896aca2d3b3f7a97dd3
Reviewed-on: https://chromium-review.googlesource.com/1249734Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Jonathan Metzman <metzman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595131}

build/config/win/BUILD.gn

@@ -136,7 +136,7 @@ config("compiler") {
     ldflags += [ "/TIMESTAMP:" + build_timestamp ]
   }
 
-  if (!is_debug && !is_component_build && !use_libfuzzer) {
+  if (!is_debug && !is_component_build) {
     # Enable standard linker optimizations like GC (/OPT:REF) and ICF in static
     # release builds. These are implied by /PROFILE below, but /PROFILE is
     # incompatible with /debug:fastlink and LLD ignores it as of this writing.