Fix some VS 2015 warnings

Fix some warnings when compiling crashpad with VC++ 2015 Update 1.

Warning 4302 occurs if you convert from a pointer to a <sizeof(void*)
integer in one cast, because this often indicates an accidental pointer
truncation which can be a bug in 64-bit builds.

Warning 4577 warns that noexcept will not be enforced, but we don't want
it to be enforced anyway, so I disabled it. The full warning is:

warning C4577: 'noexcept' used with no exception handling mode specified
termination on exception is not guaranteed. Specify /EHsc

BUG=440500
R=mark@chromium.org

Review URL: https://codereview.chromium.org/1527803002 .

Patch from Bruce Dawson <brucedawson@chromium.org>.

snapshot/win/pe_image_reader.cc

@@ -200,8 +200,10 @@ bool PEImageReader::VSFixedFileInfo(
 
   WinVMAddress address;
   WinVMSize size;
+  const uint16_t vs_file_info_type = static_cast<uint16_t>(
+      reinterpret_cast<uintptr_t>(VS_FILE_INFO));  // RT_VERSION
   if (!resource_reader.FindResourceByID(
-          reinterpret_cast<uint16_t>(VS_FILE_INFO),  // RT_VERSION
+          vs_file_info_type,
           VS_VERSION_INFO,
           MAKELANGID(LANG_NEUTRAL, SUBLANG_NEUTRAL),
           &address,

util/util.gyp

@@ -259,6 +259,7 @@
           },
           'msvs_disabled_warnings': [
             4201,  # nonstandard extension used : nameless struct/union.
+            4577,  # 'noexcept' used with no exception handling mode specified
           ],
           'conditions': [
             ['target_arch=="ia32"', {