RP2040: Add xPortIsInsideInterrupt to match other ARM ports (#1356) #3168

Job	Run time
CMake Example with Native GCC	31s
WIN32 MingW	3m 42s
GNU ARM Toolchain	1m 33s
WIN32 MSVC	2m 30s
Native GCC (macos-latest)	2m 35s
GCC MicroBlaze Toolchain	2m 52s
GNU MSP430 Toolchain	1m 40s
Native GCC (ubuntu-latest)	1m 26s
	16m 49s

Provide feedback