Remove old clang-cl workaround

Looks like this has since been fixed (or isn't hitting GTest anymore for
some reason).

Bug: chromium:772117
Change-Id: I2c2fb694e4429281e20fd252ef9c2c34e29a425c
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/56570
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1cb7226..a2d45ae 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -137,9 +137,6 @@
     # as -Weverything, to match MSVC. Instead -W3 is the alias for -Wall.
     # See http://llvm.org/viewvc/llvm-project?view=revision&revision=319116
     set(C_CXX_FLAGS "${C_CXX_FLAGS} -W3 -Wno-unused-parameter -fmsc-version=1900")
-    # googletest suppresses warning C4996 via a pragma, but clang-cl does not
-    # honor it. Suppress it here to compensate. See https://crbug.com/772117.
-    set(C_CXX_FLAGS "${C_CXX_FLAGS} -Wno-deprecated-declarations")
   else()
     if(EMSCRIPTEN)
       # emscripten's emcc/clang does not accept the "-ggdb" flag.