Has a CPU with Highlevel language (C/C++) as machine code ever been designed?
In a way, depending on whether you consider Forth to be a high-level language. There have been chips that can execute Forth directly.

Here's one reference that mentions the Harris RTX2000, as well as a Verilog implementation for an FPGA.

Here's an extensive list of them: Forth chips, including the Novix NC4000 by Chuck Moore himself.

As anyone who has implemented Forth knows, you start by defining a set of "primitive" operations from which all other operations can be built. On an ordinary processor, those primitives are implemented in the machine code of the CPU. On a Forth chip, they are implemented directly in the hardware. All other functionality, including the text interpreter/compiler, is built using those primitives. That's about as close as any chip gets to "executing HLL directly".

There are also Java bytecode chips, which don't actually execute a high level language directly, but rather an intermediate representation.