This fixes build on, at least, NetBSD 8.1 with gcc 5.5 and SmartOS with gcc 7.

This reverts commit 911e3040fa597e6a82351375d9eb416a6d3fae3a.

Currently, the generated header file might cause warnings if user specifies `-Wconversion` compiler option. This commit should be able to fix it.

When browsing around the strutil files I found a function
that was never referenced inside the code base
"void StripString(string* s, const char* remove,
-                                 char replacewith);"

The name was kind of misleading as well and it seems like
it's a carbon copy of
"void ReplaceCharacters(string* s, const char* remove,
                                       char replacewith);"
(even the parameter names are the same, the code is the same..)

Is it intentional? Maybe for compatibility reasons? If so,
let's make it deprecated and use the ReplaceCharacters method inside
or the other way around.

Also, noticed there were no tests for "StripString" or "Replace".
Added some for both and planning on maybe making it more C++ish (?)
in another commit.

* Cherry pick changes on update_version.py #6643

* Update version to 3.10.0-rc-0

* Do not add rc0 to php packages.xml

* Down integrate to GitHub

* Remove unintentional double assign

* Change ByteCountInt64 to int64_t

* Revert changes in binary_conformance_test.cc

* Revert unnecessary changes

Add comment explaining IExtensionMessage instability

Fix generated group code missing end group tag case
Fix generated field classes searching for presence index for extensions

clang-cl requires the order to be the opposite of what it currently is.
It should not affect other compilers since this is the only compiler
that has both macros defined.