Convert EMotionFX runtime uint32 -> size_t

This allows the EMotionFX runtime to compile with `/we4267` enabled, which
emits a warning when converting from `size_t` to a smaller type. All tests
for the runtime have been updated accordingly, and they pass.

In instances where a range-for loop could be used, or a std algorithm, that
was used instead of using `size_t numItems = vec.size()` and a for loop.

Casts to `uint32` were removed where possible. Some places remain, like in
the file formats.

Signed-off-by: Chris Burel <burelc@amazon.com>

Gems/EMotionFX/Code/MCore/Source/StringIdPool.cpp

@@ -43,7 +43,7 @@ namespace MCore
     AZ::u32 StringIdPool::GenerateIdForStringWithoutLock(const AZStd::string& objectName)
     {
         // Try to insert it, if we hit a collision, we have the element.
-        auto iterator = mStringToIndex.emplace(objectName, static_cast<AZ::u32>(mStrings.size()));
+        auto iterator = mStringToIndex.emplace(objectName, aznumeric_caster(mStrings.size()));
         if (!iterator.second)
         {
             // could not insert, we have the element
@@ -148,7 +148,7 @@ namespace MCore
         /// Convert binary data to text.
         size_t DataToText(AZ::IO::GenericStream& in, AZ::IO::GenericStream& out, bool /*isDataBigEndian = false*/)
         {
-            size_t dataSize = static_cast<size_t>(in.GetLength());
+            AZ::u64 dataSize = in.GetLength();
 
             AZStd::string outText;
             outText.resize(dataSize);