Function extractTypeNameFromFunctionName used by GC_TRACING add the support for compiler MSVC

1. Modify the WTF_PRETTY_FUNCTION in COMPILER(MSVC) branch in wtf/Compiler.h. from __FUNCDNAME__ to __FUNCSIG__. Because __FUNCDNAME__ give us a encode string, but __FUNCSIG__ give us a readable string.
2. Add a branch for COMPILER(MSVC) in extractTypeNameFromFunctionName.
3. Modify the default return of extractTypeNameFromFunctionName for the compliers not supported. A null String return may cause crash as described in BUG 396988.

R=oilpan-reviews@chromium.org, tkent@chromium.org
BUG=396988

Review URL: https://codereview.chromium.org/422093004

git-svn-id: svn://svn.chromium.org/blink/trunk@179459 bbb929c8-8fbe-4397-9dbb-9b2b20218538