Nothing uses these macros and removing them makes it more likely
that future code will use CASE_CFN_* instead.

Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.

gcc/
	* tree.h (BUILTIN_EXP10_P, BUILTIN_EXPONENT_P, BUILTIN_SQRT_P)
	(BUILTIN_CBRT_P, BUILTIN_ROOT_P): Delete.

From-SVN: r230489