Make warnings in assertions fire for GCC/Clang again

The old code caused warnings to fire under MSVC, and Clang <3.8.
I could not find a GCC version where it worked, but I assume that it
did at some point.

This new code causes all of MSVC, GCC, Clang, in current versions,
to emit signed/unsigned comparison warning in test like this:

```cpp
TEST_CASE() {
    int32_t i = -1;
    uint32_t j = 1;
    REQUIRE(i != j);
}
```

Where previously only MSVC would emit the warning.

Fixes #1880

include/internal/catch_capture.hpp

@@ -41,6 +41,8 @@
 ///////////////////////////////////////////////////////////////////////////////
 #define INTERNAL_CATCH_TEST( macroName, resultDisposition, ... ) \
     do { \
+        /* The expression should not be evaluated, but warnings should hopefully be checked */ \
+        CATCH_INTERNAL_IGNORE_BUT_WARN(__VA_ARGS__); \
         Catch::AssertionHandler catchAssertionHandler( macroName##_catch_sr, CATCH_INTERNAL_LINEINFO, CATCH_INTERNAL_STRINGIFY(__VA_ARGS__), resultDisposition ); \
         INTERNAL_CATCH_TRY { \
             CATCH_INTERNAL_START_WARNINGS_SUPPRESSION \
@@ -49,8 +51,7 @@
             CATCH_INTERNAL_STOP_WARNINGS_SUPPRESSION \
         } INTERNAL_CATCH_CATCH( catchAssertionHandler ) \
         INTERNAL_CATCH_REACT( catchAssertionHandler ) \
-    } while( (void)0, (false) && static_cast<bool>( !!(__VA_ARGS__) ) ) // the expression here is never evaluated at runtime but it forces the compiler to give it a look
-    // The double negation silences MSVC's C4800 warning, the static_cast forces short-circuit evaluation if the type has overloaded &&.
+    } while( false )
 
 ///////////////////////////////////////////////////////////////////////////////
 #define INTERNAL_CATCH_IF( macroName, resultDisposition, ... ) \