[SYCL][NFCI] Address static analyzer concerns (#16296)

Two changes were made:

Special `padding` field in accessors is now zero-initialized. We
construct a `host_accessor` object in our stream implementation and
static analyzer complained that some of the accessor's fields were
uninitialized. It is not like we even reference `padding` field from
anywhere, but the code change seems small, so I decided to add the
initializer.

Fixed a condition to prevent access to an array of `N` elements at index
`N`, which is outside of the array because they are 0-indexed.

---------

Co-authored-by: Marcos Maronas <[email protected]>

Author: AlexeySachkov

sycl/include/sycl/accessor.hpp

@@ -807,7 +807,7 @@ class __SYCL_EBO __SYCL_SPECIAL_CLASS __SYCL_TYPE(accessor) accessor :
 
   char padding[sizeof(detail::AccessorImplDevice<AdjustedDim>) +
                sizeof(PtrType) - sizeof(detail::AccessorBaseHost) -
-               sizeof(MAccData)];
+               sizeof(MAccData)] = {0};
 
   PtrType getQualifiedPtr() const noexcept {
     if constexpr (IsHostBuf)
@@ -2192,7 +2192,7 @@ class __SYCL_SPECIAL_CLASS local_accessor_base :
       : detail::LocalAccessorBaseHost{Impl} {}
 
   char padding[sizeof(detail::LocalAccessorBaseDevice<AdjustedDim>) +
-               sizeof(PtrType) - sizeof(detail::LocalAccessorBaseHost)];
+               sizeof(PtrType) - sizeof(detail::LocalAccessorBaseHost)] = {0};
   using detail::LocalAccessorBaseHost::getSize;
 
   PtrType getQualifiedPtr() const {

sycl/source/detail/config.cpp

@@ -106,8 +106,8 @@ void readConfig(bool ForceInitialization) {
       // Finding the position of '='
       Position = BufString.find("=");
       // Checking that the variable name is less than MAX_CONFIG_NAME and more
-      // than zero character
-      if ((Position <= MAX_CONFIG_NAME) && (Position > 0)) {
+      // than zero characters.
+      if ((Position < MAX_CONFIG_NAME) && (Position > 0)) {
         // Checking that the value is less than MAX_CONFIG_VALUE and
         // more than zero character
         if ((BufString.length() - (Position + 1) <= MAX_CONFIG_VALUE) &&