Move LazyExpr's and MessageInfo's implementation to the combined TU

Some of the implementations were inlined instead.

src/catch2/internal/catch_lazy_expr.cpp

@@ -1,30 +0,0 @@
-#include <catch2/internal/catch_lazy_expr.hpp>
-
-#include <catch2/internal/catch_decomposer.hpp>
-
-
-namespace Catch {
-
-    namespace {
-        auto operator <<(std::ostream& os, ITransientExpression const& expr) -> std::ostream& {
-            expr.streamReconstructedExpression(os);
-            return os;
-        }
-    }
-
-    auto operator << (std::ostream& os, LazyExpression const& lazyExpr) -> std::ostream& {
-        if (lazyExpr.m_isNegated)
-            os << "!";
-
-        if (lazyExpr) {
-            if (lazyExpr.m_isNegated && lazyExpr.m_transientExpression->isBinaryExpression())
-                os << "(" << *lazyExpr.m_transientExpression << ")";
-            else
-                os << *lazyExpr.m_transientExpression;
-        } else {
-            os << "{** error - unchecked empty expression requested **}";
-        }
-        return os;
-    }
-
-} // namespace Catch